snapshot of https://github.com/ent/ent.git (master, 2026-09-15; blobs > 131072B omitted)

examples/o2orecur/ent/client.go

@@ -0,0 +1,377 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated by ent, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log"
+	"reflect"
+
+	"entgo.io/ent"
+	"entgo.io/ent/examples/o2orecur/ent/migrate"
+
+	"entgo.io/ent/dialect"
+	"entgo.io/ent/dialect/sql"
+	"entgo.io/ent/dialect/sql/sqlgraph"
+	"entgo.io/ent/examples/o2orecur/ent/node"
+)
+
+// Client is the client that holds all ent builders.
+type Client struct {
+	config
+	// Schema is the client for creating, migrating and dropping schema.
+	Schema *migrate.Schema
+	// Node is the client for interacting with the Node builders.
+	Node *NodeClient
+}
+
+// NewClient creates a new client configured with the given options.
+func NewClient(opts ...Option) *Client {
+	client := &Client{config: newConfig(opts...)}
+	client.init()
+	return client
+}
+
+func (c *Client) init() {
+	c.Schema = migrate.NewSchema(c.driver)
+	c.Node = NewNodeClient(c.config)
+}
+
+type (
+	// config is the configuration for the client and its builder.
+	config struct {
+		// driver used for executing database requests.
+		driver dialect.Driver
+		// debug enable a debug logging.
+		debug bool
+		// log used for logging on debug mode.
+		log func(...any)
+		// hooks to execute on mutations.
+		hooks *hooks
+		// interceptors to execute on queries.
+		inters *inters
+	}
+	// Option function to configure the client.
+	Option func(*config)
+)
+
+// newConfig creates a new config for the client.
+func newConfig(opts ...Option) config {
+	cfg := config{log: log.Println, hooks: &hooks{}, inters: &inters{}}
+	cfg.options(opts...)
+	return cfg
+}
+
+// options applies the options on the config object.
+func (c *config) options(opts ...Option) {
+	for _, opt := range opts {
+		opt(c)
+	}
+	if c.debug {
+		c.driver = dialect.Debug(c.driver, c.log)
+	}
+}
+
+// Debug enables debug logging on the ent.Driver.
+func Debug() Option {
+	return func(c *config) {
+		c.debug = true
+	}
+}
+
+// Log sets the logging function for debug mode.
+func Log(fn func(...any)) Option {
+	return func(c *config) {
+		c.log = fn
+	}
+}
+
+// Driver configures the client driver.
+func Driver(driver dialect.Driver) Option {
+	return func(c *config) {
+		c.driver = driver
+	}
+}
+
+// Open opens a database/sql.DB specified by the driver name and
+// the data source name, and returns a new client attached to it.
+// Optional parameters can be added for configuring the client.
+func Open(driverName, dataSourceName string, options ...Option) (*Client, error) {
+	switch driverName {
+	case dialect.MySQL, dialect.Postgres, dialect.SQLite:
+		drv, err := sql.Open(driverName, dataSourceName)
+		if err != nil {
+			return nil, err
+		}
+		return NewClient(append(options, Driver(drv))...), nil
+	default:
+		return nil, fmt.Errorf("unsupported driver: %q", driverName)
+	}
+}
+
+// ErrTxStarted is returned when trying to start a new transaction from a transactional client.
+var ErrTxStarted = errors.New("ent: cannot start a transaction within a transaction")
+
+// Tx returns a new transactional client. The provided context
+// is used until the transaction is committed or rolled back.
+func (c *Client) Tx(ctx context.Context) (*Tx, error) {
+	if _, ok := c.driver.(*txDriver); ok {
+		return nil, ErrTxStarted
+	}
+	tx, err := newTx(ctx, c.driver)
+	if err != nil {
+		return nil, fmt.Errorf("ent: starting a transaction: %w", err)
+	}
+	cfg := c.config
+	cfg.driver = tx
+	return &Tx{
+		ctx:    ctx,
+		config: cfg,
+		Node:   NewNodeClient(cfg),
+	}, nil
+}
+
+// BeginTx returns a transactional client with specified options.
+func (c *Client) BeginTx(ctx context.Context, opts *sql.TxOptions) (*Tx, error) {
+	if _, ok := c.driver.(*txDriver); ok {
+		return nil, errors.New("ent: cannot start a transaction within a transaction")
+	}
+	tx, err := c.driver.(interface {
+		BeginTx(context.Context, *sql.TxOptions) (dialect.Tx, error)
+	}).BeginTx(ctx, opts)
+	if err != nil {
+		return nil, fmt.Errorf("ent: starting a transaction: %w", err)
+	}
+	cfg := c.config
+	cfg.driver = &txDriver{tx: tx, drv: c.driver}
+	return &Tx{
+		ctx:    ctx,
+		config: cfg,
+		Node:   NewNodeClient(cfg),
+	}, nil
+}
+
+// Debug returns a new debug-client. It's used to get verbose logging on specific operations.
+//
+//	client.Debug().
+//		Node.
+//		Query().
+//		Count(ctx)
+func (c *Client) Debug() *Client {
+	if c.debug {
+		return c
+	}
+	cfg := c.config
+	cfg.driver = dialect.Debug(c.driver, c.log)
+	client := &Client{config: cfg}
+	client.init()
+	return client
+}
+
+// Close closes the database connection and prevents new queries from starting.
+func (c *Client) Close() error {
+	return c.driver.Close()
+}
+
+// Use adds the mutation hooks to all the entity clients.
+// In order to add hooks to a specific client, call: `client.Node.Use(...)`.
+func (c *Client) Use(hooks ...Hook) {
+	c.Node.Use(hooks...)
+}
+
+// Intercept adds the query interceptors to all the entity clients.
+// In order to add interceptors to a specific client, call: `client.Node.Intercept(...)`.
+func (c *Client) Intercept(interceptors ...Interceptor) {
+	c.Node.Intercept(interceptors...)
+}
+
+// Mutate implements the ent.Mutator interface.
+func (c *Client) Mutate(ctx context.Context, m Mutation) (Value, error) {
+	switch m := m.(type) {
+	case *NodeMutation:
+		return c.Node.mutate(ctx, m)
+	default:
+		return nil, fmt.Errorf("ent: unknown mutation type %T", m)
+	}
+}
+
+// NodeClient is a client for the Node schema.
+type NodeClient struct {
+	config
+}
+
+// NewNodeClient returns a client for the Node from the given config.
+func NewNodeClient(c config) *NodeClient {
+	return &NodeClient{config: c}
+}
+
+// Use adds a list of mutation hooks to the hooks stack.
+// A call to `Use(f, g, h)` equals to `node.Hooks(f(g(h())))`.
+func (c *NodeClient) Use(hooks ...Hook) {
+	c.hooks.Node = append(c.hooks.Node, hooks...)
+}
+
+// Intercept adds a list of query interceptors to the interceptors stack.
+// A call to `Intercept(f, g, h)` equals to `node.Intercept(f(g(h())))`.
+func (c *NodeClient) Intercept(interceptors ...Interceptor) {
+	c.inters.Node = append(c.inters.Node, interceptors...)
+}
+
+// Create returns a builder for creating a Node entity.
+func (c *NodeClient) Create() *NodeCreate {
+	mutation := newNodeMutation(c.config, OpCreate)
+	return &NodeCreate{config: c.config, hooks: c.Hooks(), mutation: mutation}
+}
+
+// CreateBulk returns a builder for creating a bulk of Node entities.
+func (c *NodeClient) CreateBulk(builders ...*NodeCreate) *NodeCreateBulk {
+	return &NodeCreateBulk{config: c.config, builders: builders}
+}
+
+// MapCreateBulk creates a bulk creation builder from the given slice. For each item in the slice, the function creates
+// a builder and applies setFunc on it.
+func (c *NodeClient) MapCreateBulk(slice any, setFunc func(*NodeCreate, int)) *NodeCreateBulk {
+	rv := reflect.ValueOf(slice)
+	if rv.Kind() != reflect.Slice {
+		return &NodeCreateBulk{err: fmt.Errorf("calling to NodeClient.MapCreateBulk with wrong type %T, need slice", slice)}
+	}
+	builders := make([]*NodeCreate, rv.Len())
+	for i := 0; i < rv.Len(); i++ {
+		builders[i] = c.Create()
+		setFunc(builders[i], i)
+	}
+	return &NodeCreateBulk{config: c.config, builders: builders}
+}
+
+// Update returns an update builder for Node.
+func (c *NodeClient) Update() *NodeUpdate {
+	mutation := newNodeMutation(c.config, OpUpdate)
+	return &NodeUpdate{config: c.config, hooks: c.Hooks(), mutation: mutation}
+}
+
+// UpdateOne returns an update builder for the given entity.
+func (c *NodeClient) UpdateOne(_m *Node) *NodeUpdateOne {
+	mutation := newNodeMutation(c.config, OpUpdateOne, withNode(_m))
+	return &NodeUpdateOne{config: c.config, hooks: c.Hooks(), mutation: mutation}
+}
+
+// UpdateOneID returns an update builder for the given id.
+func (c *NodeClient) UpdateOneID(id int) *NodeUpdateOne {
+	mutation := newNodeMutation(c.config, OpUpdateOne, withNodeID(id))
+	return &NodeUpdateOne{config: c.config, hooks: c.Hooks(), mutation: mutation}
+}
+
+// Delete returns a delete builder for Node.
+func (c *NodeClient) Delete() *NodeDelete {
+	mutation := newNodeMutation(c.config, OpDelete)
+	return &NodeDelete{config: c.config, hooks: c.Hooks(), mutation: mutation}
+}
+
+// DeleteOne returns a builder for deleting the given entity.
+func (c *NodeClient) DeleteOne(_m *Node) *NodeDeleteOne {
+	return c.DeleteOneID(_m.ID)
+}
+
+// DeleteOneID returns a builder for deleting the given entity by its id.
+func (c *NodeClient) DeleteOneID(id int) *NodeDeleteOne {
+	builder := c.Delete().Where(node.ID(id))
+	builder.mutation.id = &id
+	builder.mutation.SetOp(OpDeleteOne)
+	return &NodeDeleteOne{builder}
+}
+
+// Query returns a query builder for Node.
+func (c *NodeClient) Query() *NodeQuery {
+	return &NodeQuery{
+		config: c.config,
+		ctx:    &QueryContext{Type: TypeNode},
+		inters: c.Interceptors(),
+	}
+}
+
+// Get returns a Node entity by its id.
+func (c *NodeClient) Get(ctx context.Context, id int) (*Node, error) {
+	return c.Query().Where(node.ID(id)).Only(ctx)
+}
+
+// GetX is like Get, but panics if an error occurs.
+func (c *NodeClient) GetX(ctx context.Context, id int) *Node {
+	obj, err := c.Get(ctx, id)
+	if err != nil {
+		panic(err)
+	}
+	return obj
+}
+
+// QueryPrev queries the prev edge of a Node.
+func (c *NodeClient) QueryPrev(_m *Node) *NodeQuery {
+	query := (&NodeClient{config: c.config}).Query()
+	query.path = func(context.Context) (fromV *sql.Selector, _ error) {
+		id := _m.ID
+		step := sqlgraph.NewStep(
+			sqlgraph.From(node.Table, node.FieldID, id),
+			sqlgraph.To(node.Table, node.FieldID),
+			sqlgraph.Edge(sqlgraph.O2O, true, node.PrevTable, node.PrevColumn),
+		)
+		fromV = sqlgraph.Neighbors(_m.driver.Dialect(), step)
+		return fromV, nil
+	}
+	return query
+}
+
+// QueryNext queries the next edge of a Node.
+func (c *NodeClient) QueryNext(_m *Node) *NodeQuery {
+	query := (&NodeClient{config: c.config}).Query()
+	query.path = func(context.Context) (fromV *sql.Selector, _ error) {
+		id := _m.ID
+		step := sqlgraph.NewStep(
+			sqlgraph.From(node.Table, node.FieldID, id),
+			sqlgraph.To(node.Table, node.FieldID),
+			sqlgraph.Edge(sqlgraph.O2O, false, node.NextTable, node.NextColumn),
+		)
+		fromV = sqlgraph.Neighbors(_m.driver.Dialect(), step)
+		return fromV, nil
+	}
+	return query
+}
+
+// Hooks returns the client hooks.
+func (c *NodeClient) Hooks() []Hook {
+	return c.hooks.Node
+}
+
+// Interceptors returns the client interceptors.
+func (c *NodeClient) Interceptors() []Interceptor {
+	return c.inters.Node
+}
+
+func (c *NodeClient) mutate(ctx context.Context, m *NodeMutation) (Value, error) {
+	switch m.Op() {
+	case OpCreate:
+		return (&NodeCreate{config: c.config, hooks: c.Hooks(), mutation: m}).Save(ctx)
+	case OpUpdate:
+		return (&NodeUpdate{config: c.config, hooks: c.Hooks(), mutation: m}).Save(ctx)
+	case OpUpdateOne:
+		return (&NodeUpdateOne{config: c.config, hooks: c.Hooks(), mutation: m}).Save(ctx)
+	case OpDelete, OpDeleteOne:
+		return (&NodeDelete{config: c.config, hooks: c.Hooks(), mutation: m}).Exec(ctx)
+	default:
+		return nil, fmt.Errorf("ent: unknown Node mutation op: %q", m.Op())
+	}
+}
+
+// hooks and interceptors per client, for fast access.
+type (
+	hooks struct {
+		Node []ent.Hook
+	}
+	inters struct {
+		Node []ent.Interceptor
+	}
+)

examples/o2orecur/ent/ent.go

@@ -0,0 +1,612 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated by ent, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"reflect"
+	"sync"
+
+	"entgo.io/ent"
+	"entgo.io/ent/dialect/sql"
+	"entgo.io/ent/dialect/sql/sqlgraph"
+	"entgo.io/ent/examples/o2orecur/ent/node"
+)
+
+// ent aliases to avoid import conflicts in user's code.
+type (
+	Op            = ent.Op
+	Hook          = ent.Hook
+	Value         = ent.Value
+	Query         = ent.Query
+	QueryContext  = ent.QueryContext
+	Querier       = ent.Querier
+	QuerierFunc   = ent.QuerierFunc
+	Interceptor   = ent.Interceptor
+	InterceptFunc = ent.InterceptFunc
+	Traverser     = ent.Traverser
+	TraverseFunc  = ent.TraverseFunc
+	Policy        = ent.Policy
+	Mutator       = ent.Mutator
+	Mutation      = ent.Mutation
+	MutateFunc    = ent.MutateFunc
+)
+
+type clientCtxKey struct{}
+
+// FromContext returns a Client stored inside a context, or nil if there isn't one.
+func FromContext(ctx context.Context) *Client {
+	c, _ := ctx.Value(clientCtxKey{}).(*Client)
+	return c
+}
+
+// NewContext returns a new context with the given Client attached.
+func NewContext(parent context.Context, c *Client) context.Context {
+	return context.WithValue(parent, clientCtxKey{}, c)
+}
+
+type txCtxKey struct{}
+
+// TxFromContext returns a Tx stored inside a context, or nil if there isn't one.
+func TxFromContext(ctx context.Context) *Tx {
+	tx, _ := ctx.Value(txCtxKey{}).(*Tx)
+	return tx
+}
+
+// NewTxContext returns a new context with the given Tx attached.
+func NewTxContext(parent context.Context, tx *Tx) context.Context {
+	return context.WithValue(parent, txCtxKey{}, tx)
+}
+
+// OrderFunc applies an ordering on the sql selector.
+// Deprecated: Use Asc/Desc functions or the package builders instead.
+type OrderFunc func(*sql.Selector)
+
+var (
+	initCheck   sync.Once
+	columnCheck sql.ColumnCheck
+)
+
+// checkColumn checks if the column exists in the given table.
+func checkColumn(t, c string) error {
+	initCheck.Do(func() {
+		columnCheck = sql.NewColumnCheck(map[string]func(string) bool{
+			node.Table: node.ValidColumn,
+		})
+	})
+	return columnCheck(t, c)
+}
+
+// Asc applies the given fields in ASC order.
+func Asc(fields ...string) func(*sql.Selector) {
+	return func(s *sql.Selector) {
+		for _, f := range fields {
+			if err := checkColumn(s.TableName(), f); err != nil {
+				s.AddError(&ValidationError{Name: f, err: fmt.Errorf("ent: %w", err)})
+			}
+			s.OrderBy(sql.Asc(s.C(f)))
+		}
+	}
+}
+
+// Desc applies the given fields in DESC order.
+func Desc(fields ...string) func(*sql.Selector) {
+	return func(s *sql.Selector) {
+		for _, f := range fields {
+			if err := checkColumn(s.TableName(), f); err != nil {
+				s.AddError(&ValidationError{Name: f, err: fmt.Errorf("ent: %w", err)})
+			}
+			s.OrderBy(sql.Desc(s.C(f)))
+		}
+	}
+}
+
+// AggregateFunc applies an aggregation step on the group-by traversal/selector.
+type AggregateFunc func(*sql.Selector) string
+
+// As is a pseudo aggregation function for renaming another other functions with custom names. For example:
+//
+//	GroupBy(field1, field2).
+//	Aggregate(ent.As(ent.Sum(field1), "sum_field1"), (ent.As(ent.Sum(field2), "sum_field2")).
+//	Scan(ctx, &v)
+func As(fn AggregateFunc, end string) AggregateFunc {
+	return func(s *sql.Selector) string {
+		return sql.As(fn(s), end)
+	}
+}
+
+// Count applies the "count" aggregation function on each group.
+func Count() AggregateFunc {
+	return func(s *sql.Selector) string {
+		return sql.Count("*")
+	}
+}
+
+// Max applies the "max" aggregation function on the given field of each group.
+func Max(field string) AggregateFunc {
+	return func(s *sql.Selector) string {
+		if err := checkColumn(s.TableName(), field); err != nil {
+			s.AddError(&ValidationError{Name: field, err: fmt.Errorf("ent: %w", err)})
+			return ""
+		}
+		return sql.Max(s.C(field))
+	}
+}
+
+// Mean applies the "mean" aggregation function on the given field of each group.
+func Mean(field string) AggregateFunc {
+	return func(s *sql.Selector) string {
+		if err := checkColumn(s.TableName(), field); err != nil {
+			s.AddError(&ValidationError{Name: field, err: fmt.Errorf("ent: %w", err)})
+			return ""
+		}
+		return sql.Avg(s.C(field))
+	}
+}
+
+// Min applies the "min" aggregation function on the given field of each group.
+func Min(field string) AggregateFunc {
+	return func(s *sql.Selector) string {
+		if err := checkColumn(s.TableName(), field); err != nil {
+			s.AddError(&ValidationError{Name: field, err: fmt.Errorf("ent: %w", err)})
+			return ""
+		}
+		return sql.Min(s.C(field))
+	}
+}
+
+// Sum applies the "sum" aggregation function on the given field of each group.
+func Sum(field string) AggregateFunc {
+	return func(s *sql.Selector) string {
+		if err := checkColumn(s.TableName(), field); err != nil {
+			s.AddError(&ValidationError{Name: field, err: fmt.Errorf("ent: %w", err)})
+			return ""
+		}
+		return sql.Sum(s.C(field))
+	}
+}
+
+// ValidationError returns when validating a field or edge fails.
+type ValidationError struct {
+	Name string // Field or edge name.
+	err  error
+}
+
+// Error implements the error interface.
+func (e *ValidationError) Error() string {
+	return e.err.Error()
+}
+
+// Unwrap implements the errors.Wrapper interface.
+func (e *ValidationError) Unwrap() error {
+	return e.err
+}
+
+// IsValidationError returns a boolean indicating whether the error is a validation error.
+func IsValidationError(err error) bool {
+	if err == nil {
+		return false
+	}
+	var e *ValidationError
+	return errors.As(err, &e)
+}
+
+// NotFoundError returns when trying to fetch a specific entity and it was not found in the database.
+type NotFoundError struct {
+	label string
+}
+
+// Error implements the error interface.
+func (e *NotFoundError) Error() string {
+	return "ent: " + e.label + " not found"
+}
+
+// IsNotFound returns a boolean indicating whether the error is a not found error.
+func IsNotFound(err error) bool {
+	if err == nil {
+		return false
+	}
+	var e *NotFoundError
+	return errors.As(err, &e)
+}
+
+// MaskNotFound masks not found error.
+func MaskNotFound(err error) error {
+	if IsNotFound(err) {
+		return nil
+	}
+	return err
+}
+
+// NotSingularError returns when trying to fetch a singular entity and more then one was found in the database.
+type NotSingularError struct {
+	label string
+}
+
+// Error implements the error interface.
+func (e *NotSingularError) Error() string {
+	return "ent: " + e.label + " not singular"
+}
+
+// IsNotSingular returns a boolean indicating whether the error is a not singular error.
+func IsNotSingular(err error) bool {
+	if err == nil {
+		return false
+	}
+	var e *NotSingularError
+	return errors.As(err, &e)
+}
+
+// NotLoadedError returns when trying to get a node that was not loaded by the query.
+type NotLoadedError struct {
+	edge string
+}
+
+// Error implements the error interface.
+func (e *NotLoadedError) Error() string {
+	return "ent: " + e.edge + " edge was not loaded"
+}
+
+// IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
+func IsNotLoaded(err error) bool {
+	if err == nil {
+		return false
+	}
+	var e *NotLoadedError
+	return errors.As(err, &e)
+}
+
+// ConstraintError returns when trying to create/update one or more entities and
+// one or more of their constraints failed. For example, violation of edge or
+// field uniqueness.
+type ConstraintError struct {
+	msg  string
+	wrap error
+}
+
+// Error implements the error interface.
+func (e ConstraintError) Error() string {
+	return "ent: constraint failed: " + e.msg
+}
+
+// Unwrap implements the errors.Wrapper interface.
+func (e *ConstraintError) Unwrap() error {
+	return e.wrap
+}
+
+// IsConstraintError returns a boolean indicating whether the error is a constraint failure.
+func IsConstraintError(err error) bool {
+	if err == nil {
+		return false
+	}
+	var e *ConstraintError
+	return errors.As(err, &e)
+}
+
+// selector embedded by the different Select/GroupBy builders.
+type selector struct {
+	label string
+	flds  *[]string
+	fns   []AggregateFunc
+	scan  func(context.Context, any) error
+}
+
+// ScanX is like Scan, but panics if an error occurs.
+func (s *selector) ScanX(ctx context.Context, v any) {
+	if err := s.scan(ctx, v); err != nil {
+		panic(err)
+	}
+}
+
+// Strings returns list of strings from a selector. It is only allowed when selecting one field.
+func (s *selector) Strings(ctx context.Context) ([]string, error) {
+	if len(*s.flds) > 1 {
+		return nil, errors.New("ent: Strings is not achievable when selecting more than 1 field")
+	}
+	var v []string
+	if err := s.scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// StringsX is like Strings, but panics if an error occurs.
+func (s *selector) StringsX(ctx context.Context) []string {
+	v, err := s.Strings(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// String returns a single string from a selector. It is only allowed when selecting one field.
+func (s *selector) String(ctx context.Context) (_ string, err error) {
+	var v []string
+	if v, err = s.Strings(ctx); err != nil {
+		return
+	}
+	switch len(v) {
+	case 1:
+		return v[0], nil
+	case 0:
+		err = &NotFoundError{s.label}
+	default:
+		err = fmt.Errorf("ent: Strings returned %d results when one was expected", len(v))
+	}
+	return
+}
+
+// StringX is like String, but panics if an error occurs.
+func (s *selector) StringX(ctx context.Context) string {
+	v, err := s.String(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Ints returns list of ints from a selector. It is only allowed when selecting one field.
+func (s *selector) Ints(ctx context.Context) ([]int, error) {
+	if len(*s.flds) > 1 {
+		return nil, errors.New("ent: Ints is not achievable when selecting more than 1 field")
+	}
+	var v []int
+	if err := s.scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// IntsX is like Ints, but panics if an error occurs.
+func (s *selector) IntsX(ctx context.Context) []int {
+	v, err := s.Ints(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Int returns a single int from a selector. It is only allowed when selecting one field.
+func (s *selector) Int(ctx context.Context) (_ int, err error) {
+	var v []int
+	if v, err = s.Ints(ctx); err != nil {
+		return
+	}
+	switch len(v) {
+	case 1:
+		return v[0], nil
+	case 0:
+		err = &NotFoundError{s.label}
+	default:
+		err = fmt.Errorf("ent: Ints returned %d results when one was expected", len(v))
+	}
+	return
+}
+
+// IntX is like Int, but panics if an error occurs.
+func (s *selector) IntX(ctx context.Context) int {
+	v, err := s.Int(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Float64s returns list of float64s from a selector. It is only allowed when selecting one field.
+func (s *selector) Float64s(ctx context.Context) ([]float64, error) {
+	if len(*s.flds) > 1 {
+		return nil, errors.New("ent: Float64s is not achievable when selecting more than 1 field")
+	}
+	var v []float64
+	if err := s.scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// Float64sX is like Float64s, but panics if an error occurs.
+func (s *selector) Float64sX(ctx context.Context) []float64 {
+	v, err := s.Float64s(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Float64 returns a single float64 from a selector. It is only allowed when selecting one field.
+func (s *selector) Float64(ctx context.Context) (_ float64, err error) {
+	var v []float64
+	if v, err = s.Float64s(ctx); err != nil {
+		return
+	}
+	switch len(v) {
+	case 1:
+		return v[0], nil
+	case 0:
+		err = &NotFoundError{s.label}
+	default:
+		err = fmt.Errorf("ent: Float64s returned %d results when one was expected", len(v))
+	}
+	return
+}
+
+// Float64X is like Float64, but panics if an error occurs.
+func (s *selector) Float64X(ctx context.Context) float64 {
+	v, err := s.Float64(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Bools returns list of bools from a selector. It is only allowed when selecting one field.
+func (s *selector) Bools(ctx context.Context) ([]bool, error) {
+	if len(*s.flds) > 1 {
+		return nil, errors.New("ent: Bools is not achievable when selecting more than 1 field")
+	}
+	var v []bool
+	if err := s.scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// BoolsX is like Bools, but panics if an error occurs.
+func (s *selector) BoolsX(ctx context.Context) []bool {
+	v, err := s.Bools(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Bool returns a single bool from a selector. It is only allowed when selecting one field.
+func (s *selector) Bool(ctx context.Context) (_ bool, err error) {
+	var v []bool
+	if v, err = s.Bools(ctx); err != nil {
+		return
+	}
+	switch len(v) {
+	case 1:
+		return v[0], nil
+	case 0:
+		err = &NotFoundError{s.label}
+	default:
+		err = fmt.Errorf("ent: Bools returned %d results when one was expected", len(v))
+	}
+	return
+}
+
+// BoolX is like Bool, but panics if an error occurs.
+func (s *selector) BoolX(ctx context.Context) bool {
+	v, err := s.Bool(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// withHooks invokes the builder operation with the given hooks, if any.
+func withHooks[V Value, M any, PM interface {
+	*M
+	Mutation
+}](ctx context.Context, exec func(context.Context) (V, error), mutation PM, hooks []Hook) (value V, err error) {
+	if len(hooks) == 0 {
+		return exec(ctx)
+	}
+	var mut Mutator = MutateFunc(func(ctx context.Context, m Mutation) (Value, error) {
+		mutationT, ok := any(m).(PM)
+		if !ok {
+			return nil, fmt.Errorf("unexpected mutation type %T", m)
+		}
+		// Set the mutation to the builder.
+		*mutation = *mutationT
+		return exec(ctx)
+	})
+	for i := len(hooks) - 1; i >= 0; i-- {
+		if hooks[i] == nil {
+			return value, fmt.Errorf("ent: uninitialized hook (forgotten import ent/runtime?)")
+		}
+		mut = hooks[i](mut)
+	}
+	v, err := mut.Mutate(ctx, mutation)
+	if err != nil {
+		return value, err
+	}
+	nv, ok := v.(V)
+	if !ok {
+		return value, fmt.Errorf("unexpected node type %T returned from %T", v, mutation)
+	}
+	return nv, nil
+}
+
+// setContextOp returns a new context with the given QueryContext attached (including its op) in case it does not exist.
+func setContextOp(ctx context.Context, qc *QueryContext, op string) context.Context {
+	if ent.QueryFromContext(ctx) == nil {
+		qc.Op = op
+		ctx = ent.NewQueryContext(ctx, qc)
+	}
+	return ctx
+}
+
+func querierAll[V Value, Q interface {
+	sqlAll(context.Context, ...queryHook) (V, error)
+}]() Querier {
+	return QuerierFunc(func(ctx context.Context, q Query) (Value, error) {
+		query, ok := q.(Q)
+		if !ok {
+			return nil, fmt.Errorf("unexpected query type %T", q)
+		}
+		return query.sqlAll(ctx)
+	})
+}
+
+func querierCount[Q interface {
+	sqlCount(context.Context) (int, error)
+}]() Querier {
+	return QuerierFunc(func(ctx context.Context, q Query) (Value, error) {
+		query, ok := q.(Q)
+		if !ok {
+			return nil, fmt.Errorf("unexpected query type %T", q)
+		}
+		return query.sqlCount(ctx)
+	})
+}
+
+func withInterceptors[V Value](ctx context.Context, q Query, qr Querier, inters []Interceptor) (v V, err error) {
+	for i := len(inters) - 1; i >= 0; i-- {
+		qr = inters[i].Intercept(qr)
+	}
+	rv, err := qr.Query(ctx, q)
+	if err != nil {
+		return v, err
+	}
+	vt, ok := rv.(V)
+	if !ok {
+		return v, fmt.Errorf("unexpected type %T returned from %T. expected type: %T", vt, q, v)
+	}
+	return vt, nil
+}
+
+func scanWithInterceptors[Q1 ent.Query, Q2 interface {
+	sqlScan(context.Context, Q1, any) error
+}](ctx context.Context, rootQuery Q1, selectOrGroup Q2, inters []Interceptor, v any) error {
+	rv := reflect.ValueOf(v)
+	var qr Querier = QuerierFunc(func(ctx context.Context, q Query) (Value, error) {
+		query, ok := q.(Q1)
+		if !ok {
+			return nil, fmt.Errorf("unexpected query type %T", q)
+		}
+		if err := selectOrGroup.sqlScan(ctx, query, v); err != nil {
+			return nil, err
+		}
+		if k := rv.Kind(); k == reflect.Pointer && rv.Elem().CanInterface() {
+			return rv.Elem().Interface(), nil
+		}
+		return v, nil
+	})
+	for i := len(inters) - 1; i >= 0; i-- {
+		qr = inters[i].Intercept(qr)
+	}
+	vv, err := qr.Query(ctx, rootQuery)
+	if err != nil {
+		return err
+	}
+	switch rv2 := reflect.ValueOf(vv); {
+	case rv.IsNil(), rv2.IsNil(), rv.Kind() != reflect.Pointer:
+	case rv.Type() == rv2.Type():
+		rv.Elem().Set(rv2.Elem())
+	case rv.Elem().Type() == rv2.Type():
+		rv.Elem().Set(rv2)
+	}
+	return nil
+}
+
+// queryHook describes an internal hook for the different sqlAll methods.
+type queryHook func(context.Context, *sqlgraph.QuerySpec)

examples/o2orecur/ent/enttest/enttest.go

@@ -0,0 +1,88 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated by ent, DO NOT EDIT.
+
+package enttest
+
+import (
+	"context"
+
+	"entgo.io/ent/examples/o2orecur/ent"
+	// required by schema hooks.
+	_ "entgo.io/ent/examples/o2orecur/ent/runtime"
+
+	"entgo.io/ent/dialect/sql/schema"
+	"entgo.io/ent/examples/o2orecur/ent/migrate"
+)
+
+type (
+	// TestingT is the interface that is shared between
+	// testing.T and testing.B and used by enttest.
+	TestingT interface {
+		FailNow()
+		Error(...any)
+	}
+
+	// Option configures client creation.
+	Option func(*options)
+
+	options struct {
+		opts        []ent.Option
+		migrateOpts []schema.MigrateOption
+	}
+)
+
+// WithOptions forwards options to client creation.
+func WithOptions(opts ...ent.Option) Option {
+	return func(o *options) {
+		o.opts = append(o.opts, opts...)
+	}
+}
+
+// WithMigrateOptions forwards options to auto migration.
+func WithMigrateOptions(opts ...schema.MigrateOption) Option {
+	return func(o *options) {
+		o.migrateOpts = append(o.migrateOpts, opts...)
+	}
+}
+
+func newOptions(opts []Option) *options {
+	o := &options{}
+	for _, opt := range opts {
+		opt(o)
+	}
+	return o
+}
+
+// Open calls ent.Open and auto-run migration.
+func Open(t TestingT, driverName, dataSourceName string, opts ...Option) *ent.Client {
+	o := newOptions(opts)
+	c, err := ent.Open(driverName, dataSourceName, o.opts...)
+	if err != nil {
+		t.Error(err)
+		t.FailNow()
+	}
+	migrateSchema(t, c, o)
+	return c
+}
+
+// NewClient calls ent.NewClient and auto-run migration.
+func NewClient(t TestingT, opts ...Option) *ent.Client {
+	o := newOptions(opts)
+	c := ent.NewClient(o.opts...)
+	migrateSchema(t, c, o)
+	return c
+}
+func migrateSchema(t TestingT, c *ent.Client, o *options) {
+	tables, err := schema.CopyTables(migrate.Tables)
+	if err != nil {
+		t.Error(err)
+		t.FailNow()
+	}
+	if err := migrate.Create(context.Background(), c.Schema, tables, o.migrateOpts...); err != nil {
+		t.Error(err)
+		t.FailNow()
+	}
+}

examples/o2orecur/ent/generate.go

@@ -0,0 +1,7 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+package ent
+
+//go:generate go run -mod=mod entgo.io/ent/cmd/ent generate --header "// Copyright 2019-present Facebook Inc. All rights reserved.\n// This source code is licensed under the Apache 2.0 license found\n// in the LICENSE file in the root directory of this source tree.\n\n// Code generated by ent, DO NOT EDIT." ./schema

examples/o2orecur/ent/hook/hook.go

@@ -0,0 +1,203 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated by ent, DO NOT EDIT.
+
+package hook
+
+import (
+	"context"
+	"fmt"
+
+	"entgo.io/ent/examples/o2orecur/ent"
+)
+
+// The NodeFunc type is an adapter to allow the use of ordinary
+// function as Node mutator.
+type NodeFunc func(context.Context, *ent.NodeMutation) (ent.Value, error)
+
+// Mutate calls f(ctx, m).
+func (f NodeFunc) Mutate(ctx context.Context, m ent.Mutation) (ent.Value, error) {
+	if mv, ok := m.(*ent.NodeMutation); ok {
+		return f(ctx, mv)
+	}
+	return nil, fmt.Errorf("unexpected mutation type %T. expect *ent.NodeMutation", m)
+}
+
+// Condition is a hook condition function.
+type Condition func(context.Context, ent.Mutation) bool
+
+// And groups conditions with the AND operator.
+func And(first, second Condition, rest ...Condition) Condition {
+	return func(ctx context.Context, m ent.Mutation) bool {
+		if !first(ctx, m) || !second(ctx, m) {
+			return false
+		}
+		for _, cond := range rest {
+			if !cond(ctx, m) {
+				return false
+			}
+		}
+		return true
+	}
+}
+
+// Or groups conditions with the OR operator.
+func Or(first, second Condition, rest ...Condition) Condition {
+	return func(ctx context.Context, m ent.Mutation) bool {
+		if first(ctx, m) || second(ctx, m) {
+			return true
+		}
+		for _, cond := range rest {
+			if cond(ctx, m) {
+				return true
+			}
+		}
+		return false
+	}
+}
+
+// Not negates a given condition.
+func Not(cond Condition) Condition {
+	return func(ctx context.Context, m ent.Mutation) bool {
+		return !cond(ctx, m)
+	}
+}
+
+// HasOp is a condition testing mutation operation.
+func HasOp(op ent.Op) Condition {
+	return func(_ context.Context, m ent.Mutation) bool {
+		return m.Op().Is(op)
+	}
+}
+
+// HasAddedFields is a condition validating `.AddedField` on fields.
+func HasAddedFields(field string, fields ...string) Condition {
+	return func(_ context.Context, m ent.Mutation) bool {
+		if _, exists := m.AddedField(field); !exists {
+			return false
+		}
+		for _, field := range fields {
+			if _, exists := m.AddedField(field); !exists {
+				return false
+			}
+		}
+		return true
+	}
+}
+
+// HasClearedFields is a condition validating `.FieldCleared` on fields.
+func HasClearedFields(field string, fields ...string) Condition {
+	return func(_ context.Context, m ent.Mutation) bool {
+		if exists := m.FieldCleared(field); !exists {
+			return false
+		}
+		for _, field := range fields {
+			if exists := m.FieldCleared(field); !exists {
+				return false
+			}
+		}
+		return true
+	}
+}
+
+// HasFields is a condition validating `.Field` on fields.
+func HasFields(field string, fields ...string) Condition {
+	return func(_ context.Context, m ent.Mutation) bool {
+		if _, exists := m.Field(field); !exists {
+			return false
+		}
+		for _, field := range fields {
+			if _, exists := m.Field(field); !exists {
+				return false
+			}
+		}
+		return true
+	}
+}
+
+// If executes the given hook under condition.
+//
+//	hook.If(ComputeAverage, And(HasFields(...), HasAddedFields(...)))
+func If(hk ent.Hook, cond Condition) ent.Hook {
+	return func(next ent.Mutator) ent.Mutator {
+		return ent.MutateFunc(func(ctx context.Context, m ent.Mutation) (ent.Value, error) {
+			if cond(ctx, m) {
+				return hk(next).Mutate(ctx, m)
+			}
+			return next.Mutate(ctx, m)
+		})
+	}
+}
+
+// On executes the given hook only for the given operation.
+//
+//	hook.On(Log, ent.Delete|ent.Create)
+func On(hk ent.Hook, op ent.Op) ent.Hook {
+	return If(hk, HasOp(op))
+}
+
+// Unless skips the given hook only for the given operation.
+//
+//	hook.Unless(Log, ent.Update|ent.UpdateOne)
+func Unless(hk ent.Hook, op ent.Op) ent.Hook {
+	return If(hk, Not(HasOp(op)))
+}
+
+// FixedError is a hook returning a fixed error.
+func FixedError(err error) ent.Hook {
+	return func(ent.Mutator) ent.Mutator {
+		return ent.MutateFunc(func(context.Context, ent.Mutation) (ent.Value, error) {
+			return nil, err
+		})
+	}
+}
+
+// Reject returns a hook that rejects all operations that match op.
+//
+//	func (T) Hooks() []ent.Hook {
+//		return []ent.Hook{
+//			Reject(ent.Delete|ent.Update),
+//		}
+//	}
+func Reject(op ent.Op) ent.Hook {
+	hk := FixedError(fmt.Errorf("%s operation is not allowed", op))
+	return On(hk, op)
+}
+
+// Chain acts as a list of hooks and is effectively immutable.
+// Once created, it will always hold the same set of hooks in the same order.
+type Chain struct {
+	hooks []ent.Hook
+}
+
+// NewChain creates a new chain of hooks.
+func NewChain(hooks ...ent.Hook) Chain {
+	return Chain{append([]ent.Hook(nil), hooks...)}
+}
+
+// Hook chains the list of hooks and returns the final hook.
+func (c Chain) Hook() ent.Hook {
+	return func(mutator ent.Mutator) ent.Mutator {
+		for i := len(c.hooks) - 1; i >= 0; i-- {
+			mutator = c.hooks[i](mutator)
+		}
+		return mutator
+	}
+}
+
+// Append extends a chain, adding the specified hook
+// as the last ones in the mutation flow.
+func (c Chain) Append(hooks ...ent.Hook) Chain {
+	newHooks := make([]ent.Hook, 0, len(c.hooks)+len(hooks))
+	newHooks = append(newHooks, c.hooks...)
+	newHooks = append(newHooks, hooks...)
+	return Chain{newHooks}
+}
+
+// Extend extends a chain, adding the specified chain
+// as the last ones in the mutation flow.
+func (c Chain) Extend(chain Chain) Chain {
+	return c.Append(chain.hooks...)
+}

examples/o2orecur/ent/migrate/migrate.go

@@ -0,0 +1,68 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated by ent, DO NOT EDIT.
+
+package migrate
+
+import (
+	"context"
+	"fmt"
+	"io"
+
+	"entgo.io/ent/dialect"
+	"entgo.io/ent/dialect/sql/schema"
+)
+
+var (
+	// WithGlobalUniqueID sets the universal ids options to the migration.
+	// If this option is enabled, ent migration will allocate a 1<<32 range
+	// for the ids of each entity (table).
+	// Note that this option cannot be applied on tables that already exist.
+	WithGlobalUniqueID = schema.WithGlobalUniqueID
+	// WithDropColumn sets the drop column option to the migration.
+	// If this option is enabled, ent migration will drop old columns
+	// that were used for both fields and edges. This defaults to false.
+	WithDropColumn = schema.WithDropColumn
+	// WithDropIndex sets the drop index option to the migration.
+	// If this option is enabled, ent migration will drop old indexes
+	// that were defined in the schema. This defaults to false.
+	// Note that unique constraints are defined using `UNIQUE INDEX`,
+	// and therefore, it's recommended to enable this option to get more
+	// flexibility in the schema changes.
+	WithDropIndex = schema.WithDropIndex
+	// WithForeignKeys enables creating foreign-key in schema DDL. This defaults to true.
+	WithForeignKeys = schema.WithForeignKeys
+)
+
+// Schema is the API for creating, migrating and dropping a schema.
+type Schema struct {
+	drv dialect.Driver
+}
+
+// NewSchema creates a new schema client.
+func NewSchema(drv dialect.Driver) *Schema { return &Schema{drv: drv} }
+
+// Create creates all schema resources.
+func (s *Schema) Create(ctx context.Context, opts ...schema.MigrateOption) error {
+	return Create(ctx, s, Tables, opts...)
+}
+
+// Create creates all table resources using the given schema driver.
+func Create(ctx context.Context, s *Schema, tables []*schema.Table, opts ...schema.MigrateOption) error {
+	migrate, err := schema.NewMigrate(s.drv, opts...)
+	if err != nil {
+		return fmt.Errorf("ent/migrate: %w", err)
+	}
+	return migrate.Create(ctx, tables...)
+}
+
+// WriteTo writes the schema changes to w instead of running them against the database.
+//
+//	if err := client.Schema.WriteTo(context.Background(), os.Stdout); err != nil {
+//		log.Fatal(err)
+//	}
+func (s *Schema) WriteTo(ctx context.Context, w io.Writer, opts ...schema.MigrateOption) error {
+	return Create(ctx, &Schema{drv: &schema.WriteDriver{Writer: w, Driver: s.drv}}, Tables, opts...)
+}

examples/o2orecur/ent/migrate/schema.go

@@ -0,0 +1,43 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated by ent, DO NOT EDIT.
+
+package migrate
+
+import (
+	"entgo.io/ent/dialect/sql/schema"
+	"entgo.io/ent/schema/field"
+)
+
+var (
+	// NodesColumns holds the columns for the "nodes" table.
+	NodesColumns = []*schema.Column{
+		{Name: "id", Type: field.TypeInt, Increment: true},
+		{Name: "value", Type: field.TypeInt},
+		{Name: "prev_id", Type: field.TypeInt, Unique: true, Nullable: true},
+	}
+	// NodesTable holds the schema information for the "nodes" table.
+	NodesTable = &schema.Table{
+		Name:       "nodes",
+		Columns:    NodesColumns,
+		PrimaryKey: []*schema.Column{NodesColumns[0]},
+		ForeignKeys: []*schema.ForeignKey{
+			{
+				Symbol:     "nodes_nodes_next",
+				Columns:    []*schema.Column{NodesColumns[2]},
+				RefColumns: []*schema.Column{NodesColumns[0]},
+				OnDelete:   schema.SetNull,
+			},
+		},
+	}
+	// Tables holds all the tables in the schema.
+	Tables = []*schema.Table{
+		NodesTable,
+	}
+)
+
+func init() {
+	NodesTable.ForeignKeys[0].RefTable = NodesTable
+}

examples/o2orecur/ent/mutation.go

@@ -0,0 +1,181 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated by ent, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"sync"
+
+	"entgo.io/ent"
+	"entgo.io/ent/examples/o2orecur/ent/node"
+)
+
+const (
+	// Operation types.
+	OpCreate    = ent.OpCreate
+	OpDelete    = ent.OpDelete
+	OpDeleteOne = ent.OpDeleteOne
+	OpUpdate    = ent.OpUpdate
+	OpUpdateOne = ent.OpUpdateOne
+
+	// Node types.
+	TypeNode = "Node"
+)
+
+// NodeMutation represents an operation that mutates the Node nodes in the graph.
+type NodeMutation struct {
+	node.Mutation
+	config
+	id       *int
+	done     bool
+	oldValue func(context.Context) (*Node, error)
+}
+
+var _ ent.Mutation = (*NodeMutation)(nil)
+
+// nodeOption allows management of the mutation configuration using functional options.
+type nodeOption func(*NodeMutation)
+
+// newNodeMutation creates new mutation for the Node entity.
+func newNodeMutation(c config, op Op, opts ...nodeOption) *NodeMutation {
+	m := &NodeMutation{
+		Mutation: *node.NewMutation(op),
+		config:   c,
+	}
+	for _, opt := range opts {
+		opt(m)
+	}
+	return m
+}
+
+// ID returns the ID value in the mutation. Note that the ID is only available
+// if it was provided to the builder or after it was returned from the database.
+func (m *NodeMutation) ID() (id int, exists bool) {
+	if m.id == nil {
+		return
+	}
+	return *m.id, true
+}
+
+// withNodeID sets the ID field of the mutation.
+func withNodeID(id int) nodeOption {
+	return func(m *NodeMutation) {
+		var (
+			err   error
+			once  sync.Once
+			value *Node
+		)
+		m.oldValue = func(ctx context.Context) (*Node, error) {
+			once.Do(func() {
+				if m.done {
+					err = errors.New("querying old values post mutation is not allowed")
+				} else {
+					value, err = m.Client().Node.Get(ctx, id)
+				}
+			})
+			return value, err
+		}
+		m.id = &id
+	}
+}
+
+// withNode sets the old Node of the mutation.
+func withNode(node *Node) nodeOption {
+	return func(m *NodeMutation) {
+		m.oldValue = func(context.Context) (*Node, error) {
+			return node, nil
+		}
+		m.id = &node.ID
+	}
+}
+
+// Client returns a new `ent.Client` from the mutation. If the mutation was
+// executed in a transaction (ent.Tx), a transactional client is returned.
+func (m NodeMutation) Client() *Client {
+	client := &Client{config: m.config}
+	client.init()
+	return client
+}
+
+// Tx returns an `ent.Tx` for mutations that were executed in transactions;
+// it returns an error otherwise.
+func (m NodeMutation) Tx() (*Tx, error) {
+	if _, ok := m.driver.(*txDriver); !ok {
+		return nil, errors.New("ent: mutation is not running in a transaction")
+	}
+	tx := &Tx{config: m.config}
+	tx.init()
+	return tx, nil
+}
+
+// IDs queries the database and returns the entity ids that match the mutation's predicate.
+// That means, if the mutation is applied within a transaction with an isolation level such
+// as sql.LevelSerializable, the returned ids match the ids of the rows that will be updated
+// or updated by the mutation.
+func (m *NodeMutation) IDs(ctx context.Context) ([]int, error) {
+	switch {
+	case m.Op().Is(OpUpdateOne | OpDeleteOne):
+		id, exists := m.ID()
+		if exists {
+			return []int{id}, nil
+		}
+		fallthrough
+	case m.Op().Is(OpUpdate | OpDelete):
+		return m.Client().Node.Query().Where(m.Predicates()...).IDs(ctx)
+	default:
+		return nil, fmt.Errorf("IDs is not allowed on %s operations", m.Op())
+	}
+}
+
+// OldValue returns the old "value" field's value of the Node entity.
+// If the Node object wasn't provided to the builder, the object is fetched from the database.
+// An error is returned if the mutation operation is not UpdateOne, or the database query fails.
+func (m *NodeMutation) OldValue(ctx context.Context) (v int, err error) {
+	if !m.Op().Is(OpUpdateOne) {
+		return v, errors.New("OldValue is only allowed on UpdateOne operations")
+	}
+	if _, exists := m.ID(); !exists || m.oldValue == nil {
+		return v, errors.New("OldValue requires an ID field in the mutation")
+	}
+	oldValue, err := m.oldValue(ctx)
+	if err != nil {
+		return v, fmt.Errorf("querying old value for OldValue: %w", err)
+	}
+	return oldValue.Value, nil
+}
+
+// OldPrevID returns the old "prev_id" field's value of the Node entity.
+// If the Node object wasn't provided to the builder, the object is fetched from the database.
+// An error is returned if the mutation operation is not UpdateOne, or the database query fails.
+func (m *NodeMutation) OldPrevID(ctx context.Context) (v int, err error) {
+	if !m.Op().Is(OpUpdateOne) {
+		return v, errors.New("OldPrevID is only allowed on UpdateOne operations")
+	}
+	if _, exists := m.ID(); !exists || m.oldValue == nil {
+		return v, errors.New("OldPrevID requires an ID field in the mutation")
+	}
+	oldValue, err := m.oldValue(ctx)
+	if err != nil {
+		return v, fmt.Errorf("querying old value for OldPrevID: %w", err)
+	}
+	return oldValue.PrevID, nil
+}
+
+// OldField returns the old value of the field from the database. An error is
+// returned if the mutation operation is not UpdateOne, or the query to the
+// database failed.
+func (m *NodeMutation) OldField(ctx context.Context, name string) (ent.Value, error) {
+	switch name {
+	case node.FieldValue:
+		return m.OldValue(ctx)
+	case node.FieldPrevID:
+		return m.OldPrevID(ctx)
+	}
+	return nil, fmt.Errorf("unknown Node field %s", name)
+}

examples/o2orecur/ent/node.go

@@ -0,0 +1,162 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated by ent, DO NOT EDIT.
+
+package ent
+
+import (
+	"fmt"
+	"strings"
+
+	"entgo.io/ent"
+	"entgo.io/ent/dialect/sql"
+	"entgo.io/ent/examples/o2orecur/ent/node"
+)
+
+// Node is the model entity for the Node schema.
+type Node struct {
+	config `json:"-"`
+	// ID of the ent.
+	ID int `json:"id,omitempty"`
+	// Value holds the value of the "value" field.
+	Value int `json:"value,omitempty"`
+	// PrevID holds the value of the "prev_id" field.
+	PrevID int `json:"prev_id,omitempty"`
+	// Edges holds the relations/edges for other nodes in the graph.
+	// The values are being populated by the NodeQuery when eager-loading is set.
+	Edges        NodeEdges `json:"edges"`
+	selectValues sql.SelectValues
+}
+
+// NodeEdges holds the relations/edges for other nodes in the graph.
+type NodeEdges struct {
+	// Prev holds the value of the prev edge.
+	Prev *Node `json:"prev,omitempty"`
+	// Next holds the value of the next edge.
+	Next *Node `json:"next,omitempty"`
+	// loadedTypes holds the information for reporting if a
+	// type was loaded (or requested) in eager-loading or not.
+	loadedTypes [2]bool
+}
+
+// PrevOrErr returns the Prev value or an error if the edge
+// was not loaded in eager-loading, or loaded but was not found.
+func (e NodeEdges) PrevOrErr() (*Node, error) {
+	if e.Prev != nil {
+		return e.Prev, nil
+	} else if e.loadedTypes[0] {
+		return nil, &NotFoundError{label: node.Label}
+	}
+	return nil, &NotLoadedError{edge: "prev"}
+}
+
+// NextOrErr returns the Next value or an error if the edge
+// was not loaded in eager-loading, or loaded but was not found.
+func (e NodeEdges) NextOrErr() (*Node, error) {
+	if e.Next != nil {
+		return e.Next, nil
+	} else if e.loadedTypes[1] {
+		return nil, &NotFoundError{label: node.Label}
+	}
+	return nil, &NotLoadedError{edge: "next"}
+}
+
+// scanValues returns the types for scanning values from sql.Rows.
+func (*Node) scanValues(columns []string) ([]any, error) {
+	values := make([]any, len(columns))
+	for i := range columns {
+		switch columns[i] {
+		case node.FieldID, node.FieldValue, node.FieldPrevID:
+			values[i] = new(sql.NullInt64)
+		default:
+			values[i] = new(sql.UnknownType)
+		}
+	}
+	return values, nil
+}
+
+// assignValues assigns the values that were returned from sql.Rows (after scanning)
+// to the Node fields.
+func (_m *Node) assignValues(columns []string, values []any) error {
+	if m, n := len(values), len(columns); m < n {
+		return fmt.Errorf("mismatch number of scan values: %d != %d", m, n)
+	}
+	for i := range columns {
+		switch columns[i] {
+		case node.FieldID:
+			value, ok := values[i].(*sql.NullInt64)
+			if !ok {
+				return fmt.Errorf("unexpected type %T for field id", value)
+			}
+			_m.ID = int(value.Int64)
+		case node.FieldValue:
+			if value, ok := values[i].(*sql.NullInt64); !ok {
+				return fmt.Errorf("unexpected type %T for field value", values[i])
+			} else if value.Valid {
+				_m.Value = int(value.Int64)
+			}
+		case node.FieldPrevID:
+			if value, ok := values[i].(*sql.NullInt64); !ok {
+				return fmt.Errorf("unexpected type %T for field prev_id", values[i])
+			} else if value.Valid {
+				_m.PrevID = int(value.Int64)
+			}
+		default:
+			_m.selectValues.Set(columns[i], values[i])
+		}
+	}
+	return nil
+}
+
+// GetValue returns the ent.Value that was dynamically selected and assigned to the Node.
+// This includes values selected through modifiers, order, etc.
+func (_m *Node) GetValue(name string) (ent.Value, error) {
+	return _m.selectValues.Get(name)
+}
+
+// QueryPrev queries the "prev" edge of the Node entity.
+func (_m *Node) QueryPrev() *NodeQuery {
+	return NewNodeClient(_m.config).QueryPrev(_m)
+}
+
+// QueryNext queries the "next" edge of the Node entity.
+func (_m *Node) QueryNext() *NodeQuery {
+	return NewNodeClient(_m.config).QueryNext(_m)
+}
+
+// Update returns a builder for updating this Node.
+// Note that you need to call Node.Unwrap() before calling this method if this Node
+// was returned from a transaction, and the transaction was committed or rolled back.
+func (_m *Node) Update() *NodeUpdateOne {
+	return NewNodeClient(_m.config).UpdateOne(_m)
+}
+
+// Unwrap unwraps the Node entity that was returned from a transaction after it was closed,
+// so that all future queries will be executed through the driver which created the transaction.
+func (_m *Node) Unwrap() *Node {
+	_tx, ok := _m.config.driver.(*txDriver)
+	if !ok {
+		panic("ent: Node is not a transactional entity")
+	}
+	_m.config.driver = _tx.drv
+	return _m
+}
+
+// String implements the fmt.Stringer.
+func (_m *Node) String() string {
+	var builder strings.Builder
+	builder.WriteString("Node(")
+	builder.WriteString(fmt.Sprintf("id=%v, ", _m.ID))
+	builder.WriteString("value=")
+	builder.WriteString(fmt.Sprintf("%v", _m.Value))
+	builder.WriteString(", ")
+	builder.WriteString("prev_id=")
+	builder.WriteString(fmt.Sprintf("%v", _m.PrevID))
+	builder.WriteByte(')')
+	return builder.String()
+}
+
+// Nodes is a parsable slice of Node.
+type Nodes []*Node

examples/o2orecur/ent/node/mutation.go

@@ -0,0 +1,439 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated by ent, DO NOT EDIT.
+
+package node
+
+import (
+	"context"
+	"fmt"
+
+	"entgo.io/ent"
+	"entgo.io/ent/dialect/sql"
+	"entgo.io/ent/examples/o2orecur/ent/predicate"
+)
+
+// Mutation represents an operation that mutates the Node nodes in the graph.
+type Mutation struct {
+	op            ent.Op
+	typ           string
+	value         *int
+	addvalue      *int
+	clearedFields map[string]struct{}
+	prev          *int
+	clearedprev   bool
+	next          *int
+	clearednext   bool
+	predicates    []predicate.Node
+}
+
+// NewMutation creates a new Mutation for the Node entity.
+func NewMutation(op ent.Op) *Mutation {
+	return &Mutation{
+		op:            op,
+		typ:           "Node",
+		clearedFields: make(map[string]struct{}),
+	}
+}
+
+// Predicates returns the list of predicates set on the mutation.
+func (m *Mutation) Predicates() []predicate.Node {
+	return m.predicates
+}
+
+// SetValue sets the "value" field.
+func (m *Mutation) SetValue(i int) {
+	m.value = &i
+	m.addvalue = nil
+}
+
+// Value returns the value of the "value" field in the mutation.
+func (m *Mutation) Value() (r int, exists bool) {
+	v := m.value
+	if v == nil {
+		return
+	}
+	return *v, true
+}
+
+// AddValue adds i to the "value" field.
+func (m *Mutation) AddValue(i int) {
+	if m.addvalue != nil {
+		*m.addvalue += i
+	} else {
+		m.addvalue = &i
+	}
+}
+
+// AddedValue returns the value that was added to the "value" field in this mutation.
+func (m *Mutation) AddedValue() (r int, exists bool) {
+	v := m.addvalue
+	if v == nil {
+		return
+	}
+	return *v, true
+}
+
+// ResetValue resets all changes to the "value" field.
+func (m *Mutation) ResetValue() {
+	m.value = nil
+	m.addvalue = nil
+}
+
+// SetPrevID sets the "prev_id" field.
+func (m *Mutation) SetPrevID(i int) {
+	m.prev = &i
+}
+
+// PrevID returns the value of the "prev_id" field in the mutation.
+func (m *Mutation) PrevID() (r int, exists bool) {
+	v := m.prev
+	if v == nil {
+		return
+	}
+	return *v, true
+}
+
+// ClearPrevID clears the value of the "prev_id" field.
+func (m *Mutation) ClearPrevID() {
+	m.prev = nil
+	m.clearedFields[FieldPrevID] = struct{}{}
+}
+
+// PrevIDCleared returns if the "prev_id" field was cleared in this mutation.
+func (m *Mutation) PrevIDCleared() bool {
+	_, ok := m.clearedFields[FieldPrevID]
+	return ok
+}
+
+// ResetPrevID resets all changes to the "prev_id" field.
+func (m *Mutation) ResetPrevID() {
+	m.prev = nil
+	delete(m.clearedFields, FieldPrevID)
+}
+
+// ClearPrev clears the "prev" edge to the Node entity.
+func (m *Mutation) ClearPrev() {
+	m.clearedprev = true
+	m.clearedFields[FieldPrevID] = struct{}{}
+}
+
+// PrevCleared reports if the "prev" edge to the Node entity was cleared.
+func (m *Mutation) PrevCleared() bool {
+	return m.PrevIDCleared() || m.clearedprev
+}
+
+// PrevIDs returns the "prev" edge IDs in the mutation.
+// Note that IDs always returns len(IDs) <= 1 for unique edges, and you should use
+// PrevID instead. It exists only for internal usage by the builders.
+func (m *Mutation) PrevIDs() (ids []int) {
+	if id := m.prev; id != nil {
+		ids = append(ids, *id)
+	}
+	return
+}
+
+// ResetPrev resets all changes to the "prev" edge.
+func (m *Mutation) ResetPrev() {
+	m.prev = nil
+	m.clearedprev = false
+}
+
+// SetNextID sets the "next" edge to the Node entity by id.
+func (m *Mutation) SetNextID(id int) {
+	m.next = &id
+}
+
+// ClearNext clears the "next" edge to the Node entity.
+func (m *Mutation) ClearNext() {
+	m.clearednext = true
+}
+
+// NextCleared reports if the "next" edge to the Node entity was cleared.
+func (m *Mutation) NextCleared() bool {
+	return m.clearednext
+}
+
+// NextID returns the "next" edge ID in the mutation.
+func (m *Mutation) NextID() (id int, exists bool) {
+	if m.next != nil {
+		return *m.next, true
+	}
+	return
+}
+
+// NextIDs returns the "next" edge IDs in the mutation.
+// Note that IDs always returns len(IDs) <= 1 for unique edges, and you should use
+// NextID instead. It exists only for internal usage by the builders.
+func (m *Mutation) NextIDs() (ids []int) {
+	if id := m.next; id != nil {
+		ids = append(ids, *id)
+	}
+	return
+}
+
+// ResetNext resets all changes to the "next" edge.
+func (m *Mutation) ResetNext() {
+	m.next = nil
+	m.clearednext = false
+}
+
+// Where appends a list predicates to the Mutation builder.
+func (m *Mutation) Where(ps ...predicate.Node) {
+	m.predicates = append(m.predicates, ps...)
+}
+
+// WhereP appends storage-level predicates to the Mutation builder. Using this method,
+// users can use type-assertion to append predicates that do not depend on any generated package.
+func (m *Mutation) WhereP(ps ...func(*sql.Selector)) {
+	p := make([]predicate.Node, len(ps))
+	for i := range ps {
+		p[i] = ps[i]
+	}
+	m.Where(p...)
+}
+
+// Op returns the operation name.
+func (m *Mutation) Op() ent.Op {
+	return m.op
+}
+
+// SetOp allows setting the mutation operation.
+func (m *Mutation) SetOp(op ent.Op) {
+	m.op = op
+}
+
+// Type returns the node type of this mutation (Node).
+func (m *Mutation) Type() string {
+	return m.typ
+}
+
+// Fields returns all fields that were changed during this mutation. Note that in
+// order to get all numeric fields that were incremented/decremented, call
+// AddedFields().
+func (m *Mutation) Fields() []string {
+	fields := make([]string, 0, 2)
+	if m.value != nil {
+		fields = append(fields, FieldValue)
+	}
+	if m.prev != nil {
+		fields = append(fields, FieldPrevID)
+	}
+	return fields
+}
+
+// Field returns the value of a field with the given name. The second boolean
+// return value indicates that this field was not set, or was not defined in the
+// schema.
+func (m *Mutation) Field(name string) (ent.Value, bool) {
+	switch name {
+	case FieldValue:
+		return m.Value()
+	case FieldPrevID:
+		return m.PrevID()
+	}
+	return nil, false
+}
+
+// OldField returns the old value of the field from the database. An error is
+// returned if the mutation operation is not UpdateOne, or the query to the
+// database failed.
+func (m *Mutation) OldField(ctx context.Context, name string) (ent.Value, error) {
+	return nil, fmt.Errorf("unknown Node field %s", name)
+}
+
+// SetField sets the value of a field with the given name. It returns an error if
+// the field is not defined in the schema, or if the type mismatched the field
+// type.
+func (m *Mutation) SetField(name string, value ent.Value) error {
+	switch name {
+	case FieldValue:
+		v, ok := value.(int)
+		if !ok {
+			return fmt.Errorf("unexpected type %T for field %s", value, name)
+		}
+		m.SetValue(v)
+		return nil
+	case FieldPrevID:
+		v, ok := value.(int)
+		if !ok {
+			return fmt.Errorf("unexpected type %T for field %s", value, name)
+		}
+		m.SetPrevID(v)
+		return nil
+	}
+	return fmt.Errorf("unknown Node field %s", name)
+}
+
+// AddedFields returns all numeric fields that were incremented/decremented during
+// this mutation.
+func (m *Mutation) AddedFields() []string {
+	var fields []string
+	if m.addvalue != nil {
+		fields = append(fields, FieldValue)
+	}
+	return fields
+}
+
+// AddedField returns the numeric value that was incremented/decremented on a field
+// with the given name. The second boolean return value indicates that this field
+// was not set, or was not defined in the schema.
+func (m *Mutation) AddedField(name string) (ent.Value, bool) {
+	switch name {
+	case FieldValue:
+		return m.AddedValue()
+	}
+	return nil, false
+}
+
+// AddField adds the value to the field with the given name. It returns an error if
+// the field is not defined in the schema, or if the type mismatched the field
+// type.
+func (m *Mutation) AddField(name string, value ent.Value) error {
+	switch name {
+	case FieldValue:
+		v, ok := value.(int)
+		if !ok {
+			return fmt.Errorf("unexpected type %T for field %s", value, name)
+		}
+		m.AddValue(v)
+		return nil
+	}
+	return fmt.Errorf("unknown Node numeric field %s", name)
+}
+
+// ClearedFields returns all nullable fields that were cleared during this
+// mutation.
+func (m *Mutation) ClearedFields() []string {
+	var fields []string
+	if m.FieldCleared(FieldPrevID) {
+		fields = append(fields, FieldPrevID)
+	}
+	return fields
+}
+
+// FieldCleared returns a boolean indicating if a field with the given name was
+// cleared in this mutation.
+func (m *Mutation) FieldCleared(name string) bool {
+	_, ok := m.clearedFields[name]
+	return ok
+}
+
+// ClearField clears the value of the field with the given name. It returns an
+// error if the field is not defined in the schema.
+func (m *Mutation) ClearField(name string) error {
+	switch name {
+	case FieldPrevID:
+		m.ClearPrevID()
+		return nil
+	}
+	return fmt.Errorf("unknown Node nullable field %s", name)
+}
+
+// ResetField resets all changes in the mutation for the field with the given name.
+// It returns an error if the field is not defined in the schema.
+func (m *Mutation) ResetField(name string) error {
+	switch name {
+	case FieldValue:
+		m.ResetValue()
+		return nil
+	case FieldPrevID:
+		m.ResetPrevID()
+		return nil
+	}
+	return fmt.Errorf("unknown Node field %s", name)
+}
+
+// AddedEdges returns all edge names that were set/added in this mutation.
+func (m *Mutation) AddedEdges() []string {
+	edges := make([]string, 0, 2)
+	if m.prev != nil {
+		edges = append(edges, EdgePrev)
+	}
+	if m.next != nil {
+		edges = append(edges, EdgeNext)
+	}
+	return edges
+}
+
+// AddedIDs returns all IDs (to other nodes) that were added for the given edge
+// name in this mutation.
+func (m *Mutation) AddedIDs(name string) []ent.Value {
+	switch name {
+	case EdgePrev:
+		if id := m.prev; id != nil {
+			return []ent.Value{*id}
+		}
+	case EdgeNext:
+		if id := m.next; id != nil {
+			return []ent.Value{*id}
+		}
+	}
+	return nil
+}
+
+// RemovedEdges returns all edge names that were removed in this mutation.
+func (m *Mutation) RemovedEdges() []string {
+	edges := make([]string, 0, 2)
+	return edges
+}
+
+// RemovedIDs returns all IDs (to other nodes) that were removed for the edge with
+// the given name in this mutation.
+func (m *Mutation) RemovedIDs(name string) []ent.Value {
+	return nil
+}
+
+// ClearedEdges returns all edge names that were cleared in this mutation.
+func (m *Mutation) ClearedEdges() []string {
+	edges := make([]string, 0, 2)
+	if m.clearedprev {
+		edges = append(edges, EdgePrev)
+	}
+	if m.clearednext {
+		edges = append(edges, EdgeNext)
+	}
+	return edges
+}
+
+// EdgeCleared returns a boolean which indicates if the edge with the given name
+// was cleared in this mutation.
+func (m *Mutation) EdgeCleared(name string) bool {
+	switch name {
+	case EdgePrev:
+		return m.clearedprev
+	case EdgeNext:
+		return m.clearednext
+	}
+	return false
+}
+
+// ClearEdge clears the value of the edge with the given name. It returns an error
+// if that edge is not defined in the schema.
+func (m *Mutation) ClearEdge(name string) error {
+	switch name {
+	case EdgePrev:
+		m.ClearPrev()
+		return nil
+	case EdgeNext:
+		m.ClearNext()
+		return nil
+	}
+	return fmt.Errorf("unknown Node unique edge %s", name)
+}
+
+// ResetEdge resets all changes to the edge with the given name in this mutation.
+// It returns an error if the edge is not defined in the schema.
+func (m *Mutation) ResetEdge(name string) error {
+	switch name {
+	case EdgePrev:
+		m.ResetPrev()
+		return nil
+	case EdgeNext:
+		m.ResetNext()
+		return nil
+	}
+	return fmt.Errorf("unknown Node edge %s", name)
+}

examples/o2orecur/ent/node/node.go

@@ -0,0 +1,100 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated by ent, DO NOT EDIT.
+
+package node
+
+import (
+	"entgo.io/ent/dialect/sql"
+	"entgo.io/ent/dialect/sql/sqlgraph"
+)
+
+const (
+	// Label holds the string label denoting the node type in the database.
+	Label = "node"
+	// FieldID holds the string denoting the id field in the database.
+	FieldID = "id"
+	// FieldValue holds the string denoting the value field in the database.
+	FieldValue = "value"
+	// FieldPrevID holds the string denoting the prev_id field in the database.
+	FieldPrevID = "prev_id"
+	// EdgePrev holds the string denoting the prev edge name in mutations.
+	EdgePrev = "prev"
+	// EdgeNext holds the string denoting the next edge name in mutations.
+	EdgeNext = "next"
+	// Table holds the table name of the node in the database.
+	Table = "nodes"
+	// PrevTable is the table that holds the prev relation/edge.
+	PrevTable = "nodes"
+	// PrevColumn is the table column denoting the prev relation/edge.
+	PrevColumn = "prev_id"
+	// NextTable is the table that holds the next relation/edge.
+	NextTable = "nodes"
+	// NextColumn is the table column denoting the next relation/edge.
+	NextColumn = "prev_id"
+)
+
+// Columns holds all SQL columns for node fields.
+var Columns = []string{
+	FieldID,
+	FieldValue,
+	FieldPrevID,
+}
+
+// ValidColumn reports if the column name is valid (part of the table columns).
+func ValidColumn(column string) bool {
+	for i := range Columns {
+		if column == Columns[i] {
+			return true
+		}
+	}
+	return false
+}
+
+// OrderOption defines the ordering options for the Node queries.
+type OrderOption func(*sql.Selector)
+
+// ByID orders the results by the id field.
+func ByID(opts ...sql.OrderTermOption) OrderOption {
+	return sql.OrderByField(FieldID, opts...).ToFunc()
+}
+
+// ByValue orders the results by the value field.
+func ByValue(opts ...sql.OrderTermOption) OrderOption {
+	return sql.OrderByField(FieldValue, opts...).ToFunc()
+}
+
+// ByPrevID orders the results by the prev_id field.
+func ByPrevID(opts ...sql.OrderTermOption) OrderOption {
+	return sql.OrderByField(FieldPrevID, opts...).ToFunc()
+}
+
+// ByPrevField orders the results by prev field.
+func ByPrevField(field string, opts ...sql.OrderTermOption) OrderOption {
+	return func(s *sql.Selector) {
+		sqlgraph.OrderByNeighborTerms(s, newPrevStep(), sql.OrderByField(field, opts...))
+	}
+}
+
+// ByNextField orders the results by next field.
+func ByNextField(field string, opts ...sql.OrderTermOption) OrderOption {
+	return func(s *sql.Selector) {
+		sqlgraph.OrderByNeighborTerms(s, newNextStep(), sql.OrderByField(field, opts...))
+	}
+}
+func newPrevStep() *sqlgraph.Step {
+	return sqlgraph.NewStep(
+		sqlgraph.From(Table, FieldID),
+		sqlgraph.To(Table, FieldID),
+		sqlgraph.Edge(sqlgraph.O2O, true, PrevTable, PrevColumn),
+	)
+}
+func newNextStep() *sqlgraph.Step {
+	return sqlgraph.NewStep(
+		sqlgraph.From(Table, FieldID),
+		sqlgraph.To(Table, FieldID),
+		sqlgraph.Edge(sqlgraph.O2O, false, NextTable, NextColumn),
+	)
+}

examples/o2orecur/ent/node/where.go

@@ -0,0 +1,199 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated by ent, DO NOT EDIT.
+
+package node
+
+import (
+	"entgo.io/ent/dialect/sql"
+	"entgo.io/ent/dialect/sql/sqlgraph"
+	"entgo.io/ent/examples/o2orecur/ent/predicate"
+)
+
+// ID filters vertices based on their ID field.
+func ID(id int) predicate.Node {
+	return predicate.Node(sql.FieldEQ(FieldID, id))
+}
+
+// IDEQ applies the EQ predicate on the ID field.
+func IDEQ(id int) predicate.Node {
+	return predicate.Node(sql.FieldEQ(FieldID, id))
+}
+
+// IDNEQ applies the NEQ predicate on the ID field.
+func IDNEQ(id int) predicate.Node {
+	return predicate.Node(sql.FieldNEQ(FieldID, id))
+}
+
+// IDIn applies the In predicate on the ID field.
+func IDIn(ids ...int) predicate.Node {
+	return predicate.Node(sql.FieldIn(FieldID, ids...))
+}
+
+// IDNotIn applies the NotIn predicate on the ID field.
+func IDNotIn(ids ...int) predicate.Node {
+	return predicate.Node(sql.FieldNotIn(FieldID, ids...))
+}
+
+// IDGT applies the GT predicate on the ID field.
+func IDGT(id int) predicate.Node {
+	return predicate.Node(sql.FieldGT(FieldID, id))
+}
+
+// IDGTE applies the GTE predicate on the ID field.
+func IDGTE(id int) predicate.Node {
+	return predicate.Node(sql.FieldGTE(FieldID, id))
+}
+
+// IDLT applies the LT predicate on the ID field.
+func IDLT(id int) predicate.Node {
+	return predicate.Node(sql.FieldLT(FieldID, id))
+}
+
+// IDLTE applies the LTE predicate on the ID field.
+func IDLTE(id int) predicate.Node {
+	return predicate.Node(sql.FieldLTE(FieldID, id))
+}
+
+// Value applies equality check predicate on the "value" field. It's identical to ValueEQ.
+func Value(v int) predicate.Node {
+	return predicate.Node(sql.FieldEQ(FieldValue, v))
+}
+
+// PrevID applies equality check predicate on the "prev_id" field. It's identical to PrevIDEQ.
+func PrevID(v int) predicate.Node {
+	return predicate.Node(sql.FieldEQ(FieldPrevID, v))
+}
+
+// ValueEQ applies the EQ predicate on the "value" field.
+func ValueEQ(v int) predicate.Node {
+	return predicate.Node(sql.FieldEQ(FieldValue, v))
+}
+
+// ValueNEQ applies the NEQ predicate on the "value" field.
+func ValueNEQ(v int) predicate.Node {
+	return predicate.Node(sql.FieldNEQ(FieldValue, v))
+}
+
+// ValueIn applies the In predicate on the "value" field.
+func ValueIn(vs ...int) predicate.Node {
+	return predicate.Node(sql.FieldIn(FieldValue, vs...))
+}
+
+// ValueNotIn applies the NotIn predicate on the "value" field.
+func ValueNotIn(vs ...int) predicate.Node {
+	return predicate.Node(sql.FieldNotIn(FieldValue, vs...))
+}
+
+// ValueGT applies the GT predicate on the "value" field.
+func ValueGT(v int) predicate.Node {
+	return predicate.Node(sql.FieldGT(FieldValue, v))
+}
+
+// ValueGTE applies the GTE predicate on the "value" field.
+func ValueGTE(v int) predicate.Node {
+	return predicate.Node(sql.FieldGTE(FieldValue, v))
+}
+
+// ValueLT applies the LT predicate on the "value" field.
+func ValueLT(v int) predicate.Node {
+	return predicate.Node(sql.FieldLT(FieldValue, v))
+}
+
+// ValueLTE applies the LTE predicate on the "value" field.
+func ValueLTE(v int) predicate.Node {
+	return predicate.Node(sql.FieldLTE(FieldValue, v))
+}
+
+// PrevIDEQ applies the EQ predicate on the "prev_id" field.
+func PrevIDEQ(v int) predicate.Node {
+	return predicate.Node(sql.FieldEQ(FieldPrevID, v))
+}
+
+// PrevIDNEQ applies the NEQ predicate on the "prev_id" field.
+func PrevIDNEQ(v int) predicate.Node {
+	return predicate.Node(sql.FieldNEQ(FieldPrevID, v))
+}
+
+// PrevIDIn applies the In predicate on the "prev_id" field.
+func PrevIDIn(vs ...int) predicate.Node {
+	return predicate.Node(sql.FieldIn(FieldPrevID, vs...))
+}
+
+// PrevIDNotIn applies the NotIn predicate on the "prev_id" field.
+func PrevIDNotIn(vs ...int) predicate.Node {
+	return predicate.Node(sql.FieldNotIn(FieldPrevID, vs...))
+}
+
+// PrevIDIsNil applies the IsNil predicate on the "prev_id" field.
+func PrevIDIsNil() predicate.Node {
+	return predicate.Node(sql.FieldIsNull(FieldPrevID))
+}
+
+// PrevIDNotNil applies the NotNil predicate on the "prev_id" field.
+func PrevIDNotNil() predicate.Node {
+	return predicate.Node(sql.FieldNotNull(FieldPrevID))
+}
+
+// HasPrev applies the HasEdge predicate on the "prev" edge.
+func HasPrev() predicate.Node {
+	return predicate.Node(func(s *sql.Selector) {
+		step := sqlgraph.NewStep(
+			sqlgraph.From(Table, FieldID),
+			sqlgraph.Edge(sqlgraph.O2O, true, PrevTable, PrevColumn),
+		)
+		sqlgraph.HasNeighbors(s, step)
+	})
+}
+
+// HasPrevWith applies the HasEdge predicate on the "prev" edge with a given conditions (other predicates).
+func HasPrevWith(preds ...predicate.Node) predicate.Node {
+	return predicate.Node(func(s *sql.Selector) {
+		step := newPrevStep()
+		sqlgraph.HasNeighborsWith(s, step, func(s *sql.Selector) {
+			for _, p := range preds {
+				p(s)
+			}
+		})
+	})
+}
+
+// HasNext applies the HasEdge predicate on the "next" edge.
+func HasNext() predicate.Node {
+	return predicate.Node(func(s *sql.Selector) {
+		step := sqlgraph.NewStep(
+			sqlgraph.From(Table, FieldID),
+			sqlgraph.Edge(sqlgraph.O2O, false, NextTable, NextColumn),
+		)
+		sqlgraph.HasNeighbors(s, step)
+	})
+}
+
+// HasNextWith applies the HasEdge predicate on the "next" edge with a given conditions (other predicates).
+func HasNextWith(preds ...predicate.Node) predicate.Node {
+	return predicate.Node(func(s *sql.Selector) {
+		step := newNextStep()
+		sqlgraph.HasNeighborsWith(s, step, func(s *sql.Selector) {
+			for _, p := range preds {
+				p(s)
+			}
+		})
+	})
+}
+
+// And groups predicates with the AND operator between them.
+func And(predicates ...predicate.Node) predicate.Node {
+	return predicate.Node(sql.AndPredicates(predicates...))
+}
+
+// Or groups predicates with the OR operator between them.
+func Or(predicates ...predicate.Node) predicate.Node {
+	return predicate.Node(sql.OrPredicates(predicates...))
+}
+
+// Not applies the not operator on the given predicate.
+func Not(p predicate.Node) predicate.Node {
+	return predicate.Node(sql.NotPredicates(p))
+}

examples/o2orecur/ent/node_create.go

@@ -0,0 +1,258 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated by ent, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"entgo.io/ent/dialect/sql/sqlgraph"
+	"entgo.io/ent/examples/o2orecur/ent/node"
+	"entgo.io/ent/schema/field"
+)
+
+// NodeCreate is the builder for creating a Node entity.
+type NodeCreate struct {
+	config
+	mutation *NodeMutation
+	hooks    []Hook
+}
+
+// SetValue sets the "value" field.
+func (_c *NodeCreate) SetValue(v int) *NodeCreate {
+	_c.mutation.SetValue(v)
+	return _c
+}
+
+// SetPrevID sets the "prev_id" field.
+func (_c *NodeCreate) SetPrevID(v int) *NodeCreate {
+	_c.mutation.SetPrevID(v)
+	return _c
+}
+
+// SetNillablePrevID sets the "prev_id" field if the given value is not nil.
+func (_c *NodeCreate) SetNillablePrevID(v *int) *NodeCreate {
+	if v != nil {
+		_c.SetPrevID(*v)
+	}
+	return _c
+}
+
+// SetPrev sets the "prev" edge to the Node entity.
+func (_c *NodeCreate) SetPrev(v *Node) *NodeCreate {
+	return _c.SetPrevID(v.ID)
+}
+
+// SetNextID sets the "next" edge to the Node entity by ID.
+func (_c *NodeCreate) SetNextID(id int) *NodeCreate {
+	_c.mutation.SetNextID(id)
+	return _c
+}
+
+// SetNillableNextID sets the "next" edge to the Node entity by ID if the given value is not nil.
+func (_c *NodeCreate) SetNillableNextID(id *int) *NodeCreate {
+	if id != nil {
+		_c = _c.SetNextID(*id)
+	}
+	return _c
+}
+
+// SetNext sets the "next" edge to the Node entity.
+func (_c *NodeCreate) SetNext(v *Node) *NodeCreate {
+	return _c.SetNextID(v.ID)
+}
+
+// Mutation returns the NodeMutation object of the builder.
+func (_c *NodeCreate) Mutation() *NodeMutation {
+	return _c.mutation
+}
+
+// Save creates the Node in the database.
+func (_c *NodeCreate) Save(ctx context.Context) (*Node, error) {
+	return withHooks(ctx, _c.sqlSave, _c.mutation, _c.hooks)
+}
+
+// SaveX calls Save and panics if Save returns an error.
+func (_c *NodeCreate) SaveX(ctx context.Context) *Node {
+	v, err := _c.Save(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Exec executes the query.
+func (_c *NodeCreate) Exec(ctx context.Context) error {
+	_, err := _c.Save(ctx)
+	return err
+}
+
+// ExecX is like Exec, but panics if an error occurs.
+func (_c *NodeCreate) ExecX(ctx context.Context) {
+	if err := _c.Exec(ctx); err != nil {
+		panic(err)
+	}
+}
+
+// check runs all checks and user-defined validators on the builder.
+func (_c *NodeCreate) check() error {
+	if _, ok := _c.mutation.Value(); !ok {
+		return &ValidationError{Name: "value", err: errors.New(`ent: missing required field "Node.value"`)}
+	}
+	return nil
+}
+
+func (_c *NodeCreate) sqlSave(ctx context.Context) (*Node, error) {
+	if err := _c.check(); err != nil {
+		return nil, err
+	}
+	_node, _spec := _c.createSpec()
+	if err := sqlgraph.CreateNode(ctx, _c.driver, _spec); err != nil {
+		if sqlgraph.IsConstraintError(err) {
+			err = &ConstraintError{msg: err.Error(), wrap: err}
+		}
+		return nil, err
+	}
+	id := _spec.ID.Value.(int64)
+	_node.ID = int(id)
+	_c.mutation.id = &_node.ID
+	_c.mutation.done = true
+	return _node, nil
+}
+
+func (_c *NodeCreate) createSpec() (*Node, *sqlgraph.CreateSpec) {
+	var (
+		_node = &Node{config: _c.config}
+		_spec = sqlgraph.NewCreateSpec(node.Table, sqlgraph.NewFieldSpec(node.FieldID, field.TypeInt))
+	)
+	if value, ok := _c.mutation.Value(); ok {
+		_spec.SetField(node.FieldValue, field.TypeInt, value)
+		_node.Value = value
+	}
+	if nodes := _c.mutation.PrevIDs(); len(nodes) > 0 {
+		edge := &sqlgraph.EdgeSpec{
+			Rel:     sqlgraph.O2O,
+			Inverse: true,
+			Table:   node.PrevTable,
+			Columns: []string{node.PrevColumn},
+			Bidi:    false,
+			Target: &sqlgraph.EdgeTarget{
+				IDSpec: sqlgraph.NewFieldSpec(node.FieldID, field.TypeInt),
+			},
+		}
+		for _, k := range nodes {
+			edge.Target.Nodes = append(edge.Target.Nodes, k)
+		}
+		_node.PrevID = nodes[0]
+		_spec.Edges = append(_spec.Edges, edge)
+	}
+	if nodes := _c.mutation.NextIDs(); len(nodes) > 0 {
+		edge := &sqlgraph.EdgeSpec{
+			Rel:     sqlgraph.O2O,
+			Inverse: false,
+			Table:   node.NextTable,
+			Columns: []string{node.NextColumn},
+			Bidi:    false,
+			Target: &sqlgraph.EdgeTarget{
+				IDSpec: sqlgraph.NewFieldSpec(node.FieldID, field.TypeInt),
+			},
+		}
+		for _, k := range nodes {
+			edge.Target.Nodes = append(edge.Target.Nodes, k)
+		}
+		_spec.Edges = append(_spec.Edges, edge)
+	}
+	return _node, _spec
+}
+
+// NodeCreateBulk is the builder for creating many Node entities in bulk.
+type NodeCreateBulk struct {
+	config
+	err      error
+	builders []*NodeCreate
+}
+
+// Save creates the Node entities in the database.
+func (_c *NodeCreateBulk) Save(ctx context.Context) ([]*Node, error) {
+	if _c.err != nil {
+		return nil, _c.err
+	}
+	specs := make([]*sqlgraph.CreateSpec, len(_c.builders))
+	nodes := make([]*Node, len(_c.builders))
+	mutators := make([]Mutator, len(_c.builders))
+	for i := range _c.builders {
+		func(i int, root context.Context) {
+			builder := _c.builders[i]
+			var mut Mutator = MutateFunc(func(ctx context.Context, m Mutation) (Value, error) {
+				mutation, ok := m.(*NodeMutation)
+				if !ok {
+					return nil, fmt.Errorf("unexpected mutation type %T", m)
+				}
+				if err := builder.check(); err != nil {
+					return nil, err
+				}
+				builder.mutation = mutation
+				var err error
+				nodes[i], specs[i] = builder.createSpec()
+				if i < len(mutators)-1 {
+					_, err = mutators[i+1].Mutate(root, _c.builders[i+1].mutation)
+				} else {
+					spec := &sqlgraph.BatchCreateSpec{Nodes: specs}
+					// Invoke the actual operation on the latest mutation in the chain.
+					if err = sqlgraph.BatchCreate(ctx, _c.driver, spec); err != nil {
+						if sqlgraph.IsConstraintError(err) {
+							err = &ConstraintError{msg: err.Error(), wrap: err}
+						}
+					}
+				}
+				if err != nil {
+					return nil, err
+				}
+				mutation.id = &nodes[i].ID
+				if specs[i].ID.Value != nil {
+					id := specs[i].ID.Value.(int64)
+					nodes[i].ID = int(id)
+				}
+				mutation.done = true
+				return nodes[i], nil
+			})
+			for i := len(builder.hooks) - 1; i >= 0; i-- {
+				mut = builder.hooks[i](mut)
+			}
+			mutators[i] = mut
+		}(i, ctx)
+	}
+	if len(mutators) > 0 {
+		if _, err := mutators[0].Mutate(ctx, _c.builders[0].mutation); err != nil {
+			return nil, err
+		}
+	}
+	return nodes, nil
+}
+
+// SaveX is like Save, but panics if an error occurs.
+func (_c *NodeCreateBulk) SaveX(ctx context.Context) []*Node {
+	v, err := _c.Save(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Exec executes the query.
+func (_c *NodeCreateBulk) Exec(ctx context.Context) error {
+	_, err := _c.Save(ctx)
+	return err
+}
+
+// ExecX is like Exec, but panics if an error occurs.
+func (_c *NodeCreateBulk) ExecX(ctx context.Context) {
+	if err := _c.Exec(ctx); err != nil {
+		panic(err)
+	}
+}

examples/o2orecur/ent/node_delete.go

@@ -0,0 +1,92 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated by ent, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+
+	"entgo.io/ent/dialect/sql"
+	"entgo.io/ent/dialect/sql/sqlgraph"
+	"entgo.io/ent/examples/o2orecur/ent/node"
+	"entgo.io/ent/examples/o2orecur/ent/predicate"
+	"entgo.io/ent/schema/field"
+)
+
+// NodeDelete is the builder for deleting a Node entity.
+type NodeDelete struct {
+	config
+	hooks    []Hook
+	mutation *NodeMutation
+}
+
+// Where appends a list predicates to the NodeDelete builder.
+func (_d *NodeDelete) Where(ps ...predicate.Node) *NodeDelete {
+	_d.mutation.Where(ps...)
+	return _d
+}
+
+// Exec executes the deletion query and returns how many vertices were deleted.
+func (_d *NodeDelete) Exec(ctx context.Context) (int, error) {
+	return withHooks(ctx, _d.sqlExec, _d.mutation, _d.hooks)
+}
+
+// ExecX is like Exec, but panics if an error occurs.
+func (_d *NodeDelete) ExecX(ctx context.Context) int {
+	n, err := _d.Exec(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return n
+}
+
+func (_d *NodeDelete) sqlExec(ctx context.Context) (int, error) {
+	_spec := sqlgraph.NewDeleteSpec(node.Table, sqlgraph.NewFieldSpec(node.FieldID, field.TypeInt))
+	if ps := _d.mutation.Predicates(); len(ps) > 0 {
+		_spec.Predicate = func(selector *sql.Selector) {
+			for i := range ps {
+				ps[i](selector)
+			}
+		}
+	}
+	affected, err := sqlgraph.DeleteNodes(ctx, _d.driver, _spec)
+	if err != nil && sqlgraph.IsConstraintError(err) {
+		err = &ConstraintError{msg: err.Error(), wrap: err}
+	}
+	_d.mutation.done = true
+	return affected, err
+}
+
+// NodeDeleteOne is the builder for deleting a single Node entity.
+type NodeDeleteOne struct {
+	_d *NodeDelete
+}
+
+// Where appends a list predicates to the NodeDelete builder.
+func (_d *NodeDeleteOne) Where(ps ...predicate.Node) *NodeDeleteOne {
+	_d._d.mutation.Where(ps...)
+	return _d
+}
+
+// Exec executes the deletion query.
+func (_d *NodeDeleteOne) Exec(ctx context.Context) error {
+	n, err := _d._d.Exec(ctx)
+	switch {
+	case err != nil:
+		return err
+	case n == 0:
+		return &NotFoundError{node.Label}
+	default:
+		return nil
+	}
+}
+
+// ExecX is like Exec, but panics if an error occurs.
+func (_d *NodeDeleteOne) ExecX(ctx context.Context) {
+	if err := _d.Exec(ctx); err != nil {
+		panic(err)
+	}
+}

examples/o2orecur/ent/node_query.go

@@ -0,0 +1,679 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated by ent, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+	"database/sql/driver"
+	"fmt"
+	"math"
+
+	"entgo.io/ent"
+	"entgo.io/ent/dialect/sql"
+	"entgo.io/ent/dialect/sql/sqlgraph"
+	"entgo.io/ent/examples/o2orecur/ent/node"
+	"entgo.io/ent/examples/o2orecur/ent/predicate"
+	"entgo.io/ent/schema/field"
+)
+
+// NodeQuery is the builder for querying Node entities.
+type NodeQuery struct {
+	config
+	ctx        *QueryContext
+	order      []node.OrderOption
+	inters     []Interceptor
+	predicates []predicate.Node
+	withPrev   *NodeQuery
+	withNext   *NodeQuery
+	// intermediate query (i.e. traversal path).
+	sql  *sql.Selector
+	path func(context.Context) (*sql.Selector, error)
+}
+
+// Where adds a new predicate for the NodeQuery builder.
+func (_q *NodeQuery) Where(ps ...predicate.Node) *NodeQuery {
+	_q.predicates = append(_q.predicates, ps...)
+	return _q
+}
+
+// Limit the number of records to be returned by this query.
+func (_q *NodeQuery) Limit(limit int) *NodeQuery {
+	_q.ctx.Limit = &limit
+	return _q
+}
+
+// Offset to start from.
+func (_q *NodeQuery) Offset(offset int) *NodeQuery {
+	_q.ctx.Offset = &offset
+	return _q
+}
+
+// Unique configures the query builder to filter duplicate records on query.
+// By default, unique is set to true, and can be disabled using this method.
+func (_q *NodeQuery) Unique(unique bool) *NodeQuery {
+	_q.ctx.Unique = &unique
+	return _q
+}
+
+// Order specifies how the records should be ordered.
+func (_q *NodeQuery) Order(o ...node.OrderOption) *NodeQuery {
+	_q.order = append(_q.order, o...)
+	return _q
+}
+
+// QueryPrev chains the current query on the "prev" edge.
+func (_q *NodeQuery) QueryPrev() *NodeQuery {
+	query := (&NodeClient{config: _q.config}).Query()
+	query.path = func(ctx context.Context) (fromU *sql.Selector, err error) {
+		if err := _q.prepareQuery(ctx); err != nil {
+			return nil, err
+		}
+		selector := _q.sqlQuery(ctx)
+		if err := selector.Err(); err != nil {
+			return nil, err
+		}
+		step := sqlgraph.NewStep(
+			sqlgraph.From(node.Table, node.FieldID, selector),
+			sqlgraph.To(node.Table, node.FieldID),
+			sqlgraph.Edge(sqlgraph.O2O, true, node.PrevTable, node.PrevColumn),
+		)
+		fromU = sqlgraph.SetNeighbors(_q.driver.Dialect(), step)
+		return fromU, nil
+	}
+	return query
+}
+
+// QueryNext chains the current query on the "next" edge.
+func (_q *NodeQuery) QueryNext() *NodeQuery {
+	query := (&NodeClient{config: _q.config}).Query()
+	query.path = func(ctx context.Context) (fromU *sql.Selector, err error) {
+		if err := _q.prepareQuery(ctx); err != nil {
+			return nil, err
+		}
+		selector := _q.sqlQuery(ctx)
+		if err := selector.Err(); err != nil {
+			return nil, err
+		}
+		step := sqlgraph.NewStep(
+			sqlgraph.From(node.Table, node.FieldID, selector),
+			sqlgraph.To(node.Table, node.FieldID),
+			sqlgraph.Edge(sqlgraph.O2O, false, node.NextTable, node.NextColumn),
+		)
+		fromU = sqlgraph.SetNeighbors(_q.driver.Dialect(), step)
+		return fromU, nil
+	}
+	return query
+}
+
+// First returns the first Node entity from the query.
+// Returns a *NotFoundError when no Node was found.
+func (_q *NodeQuery) First(ctx context.Context) (*Node, error) {
+	nodes, err := _q.Limit(1).All(setContextOp(ctx, _q.ctx, ent.OpQueryFirst))
+	if err != nil {
+		return nil, err
+	}
+	if len(nodes) == 0 {
+		return nil, &NotFoundError{node.Label}
+	}
+	return nodes[0], nil
+}
+
+// FirstX is like First, but panics if an error occurs.
+func (_q *NodeQuery) FirstX(ctx context.Context) *Node {
+	node, err := _q.First(ctx)
+	if err != nil && !IsNotFound(err) {
+		panic(err)
+	}
+	return node
+}
+
+// FirstID returns the first Node ID from the query.
+// Returns a *NotFoundError when no Node ID was found.
+func (_q *NodeQuery) FirstID(ctx context.Context) (id int, err error) {
+	var ids []int
+	if ids, err = _q.Limit(1).IDs(setContextOp(ctx, _q.ctx, ent.OpQueryFirstID)); err != nil {
+		return
+	}
+	if len(ids) == 0 {
+		err = &NotFoundError{node.Label}
+		return
+	}
+	return ids[0], nil
+}
+
+// FirstIDX is like FirstID, but panics if an error occurs.
+func (_q *NodeQuery) FirstIDX(ctx context.Context) int {
+	id, err := _q.FirstID(ctx)
+	if err != nil && !IsNotFound(err) {
+		panic(err)
+	}
+	return id
+}
+
+// Only returns a single Node entity found by the query, ensuring it only returns one.
+// Returns a *NotSingularError when more than one Node entity is found.
+// Returns a *NotFoundError when no Node entities are found.
+func (_q *NodeQuery) Only(ctx context.Context) (*Node, error) {
+	nodes, err := _q.Limit(2).All(setContextOp(ctx, _q.ctx, ent.OpQueryOnly))
+	if err != nil {
+		return nil, err
+	}
+	switch len(nodes) {
+	case 1:
+		return nodes[0], nil
+	case 0:
+		return nil, &NotFoundError{node.Label}
+	default:
+		return nil, &NotSingularError{node.Label}
+	}
+}
+
+// OnlyX is like Only, but panics if an error occurs.
+func (_q *NodeQuery) OnlyX(ctx context.Context) *Node {
+	node, err := _q.Only(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return node
+}
+
+// OnlyID is like Only, but returns the only Node ID in the query.
+// Returns a *NotSingularError when more than one Node ID is found.
+// Returns a *NotFoundError when no entities are found.
+func (_q *NodeQuery) OnlyID(ctx context.Context) (id int, err error) {
+	var ids []int
+	if ids, err = _q.Limit(2).IDs(setContextOp(ctx, _q.ctx, ent.OpQueryOnlyID)); err != nil {
+		return
+	}
+	switch len(ids) {
+	case 1:
+		id = ids[0]
+	case 0:
+		err = &NotFoundError{node.Label}
+	default:
+		err = &NotSingularError{node.Label}
+	}
+	return
+}
+
+// OnlyIDX is like OnlyID, but panics if an error occurs.
+func (_q *NodeQuery) OnlyIDX(ctx context.Context) int {
+	id, err := _q.OnlyID(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return id
+}
+
+// All executes the query and returns a list of Nodes.
+func (_q *NodeQuery) All(ctx context.Context) ([]*Node, error) {
+	ctx = setContextOp(ctx, _q.ctx, ent.OpQueryAll)
+	if err := _q.prepareQuery(ctx); err != nil {
+		return nil, err
+	}
+	qr := querierAll[[]*Node, *NodeQuery]()
+	return withInterceptors[[]*Node](ctx, _q, qr, _q.inters)
+}
+
+// AllX is like All, but panics if an error occurs.
+func (_q *NodeQuery) AllX(ctx context.Context) []*Node {
+	nodes, err := _q.All(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return nodes
+}
+
+// IDs executes the query and returns a list of Node IDs.
+func (_q *NodeQuery) IDs(ctx context.Context) (ids []int, err error) {
+	if _q.ctx.Unique == nil && _q.path != nil {
+		_q.Unique(true)
+	}
+	ctx = setContextOp(ctx, _q.ctx, ent.OpQueryIDs)
+	if err = _q.Select(node.FieldID).Scan(ctx, &ids); err != nil {
+		return nil, err
+	}
+	return ids, nil
+}
+
+// IDsX is like IDs, but panics if an error occurs.
+func (_q *NodeQuery) IDsX(ctx context.Context) []int {
+	ids, err := _q.IDs(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return ids
+}
+
+// Count returns the count of the given query.
+func (_q *NodeQuery) Count(ctx context.Context) (int, error) {
+	ctx = setContextOp(ctx, _q.ctx, ent.OpQueryCount)
+	if err := _q.prepareQuery(ctx); err != nil {
+		return 0, err
+	}
+	return withInterceptors[int](ctx, _q, querierCount[*NodeQuery](), _q.inters)
+}
+
+// CountX is like Count, but panics if an error occurs.
+func (_q *NodeQuery) CountX(ctx context.Context) int {
+	count, err := _q.Count(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return count
+}
+
+// Exist returns true if the query has elements in the graph.
+func (_q *NodeQuery) Exist(ctx context.Context) (bool, error) {
+	ctx = setContextOp(ctx, _q.ctx, ent.OpQueryExist)
+	switch _, err := _q.FirstID(ctx); {
+	case IsNotFound(err):
+		return false, nil
+	case err != nil:
+		return false, fmt.Errorf("ent: check existence: %w", err)
+	default:
+		return true, nil
+	}
+}
+
+// ExistX is like Exist, but panics if an error occurs.
+func (_q *NodeQuery) ExistX(ctx context.Context) bool {
+	exist, err := _q.Exist(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return exist
+}
+
+// Clone returns a duplicate of the NodeQuery builder, including all associated steps. It can be
+// used to prepare common query builders and use them differently after the clone is made.
+func (_q *NodeQuery) Clone() *NodeQuery {
+	if _q == nil {
+		return nil
+	}
+	return &NodeQuery{
+		config:     _q.config,
+		ctx:        _q.ctx.Clone(),
+		order:      append([]node.OrderOption{}, _q.order...),
+		inters:     append([]Interceptor{}, _q.inters...),
+		predicates: append([]predicate.Node{}, _q.predicates...),
+		withPrev:   _q.withPrev.Clone(),
+		withNext:   _q.withNext.Clone(),
+		// clone intermediate query.
+		sql:  _q.sql.Clone(),
+		path: _q.path,
+	}
+}
+
+// WithPrev tells the query-builder to eager-load the nodes that are connected to
+// the "prev" edge. The optional arguments are used to configure the query builder of the edge.
+func (_q *NodeQuery) WithPrev(opts ...func(*NodeQuery)) *NodeQuery {
+	query := (&NodeClient{config: _q.config}).Query()
+	for _, opt := range opts {
+		opt(query)
+	}
+	_q.withPrev = query
+	return _q
+}
+
+// WithNext tells the query-builder to eager-load the nodes that are connected to
+// the "next" edge. The optional arguments are used to configure the query builder of the edge.
+func (_q *NodeQuery) WithNext(opts ...func(*NodeQuery)) *NodeQuery {
+	query := (&NodeClient{config: _q.config}).Query()
+	for _, opt := range opts {
+		opt(query)
+	}
+	_q.withNext = query
+	return _q
+}
+
+// GroupBy is used to group vertices by one or more fields/columns.
+// It is often used with aggregate functions, like: count, max, mean, min, sum.
+//
+// Example:
+//
+//	var v []struct {
+//		Value int `json:"value,omitempty"`
+//		Count int `json:"count,omitempty"`
+//	}
+//
+//	client.Node.Query().
+//		GroupBy(node.FieldValue).
+//		Aggregate(ent.Count()).
+//		Scan(ctx, &v)
+func (_q *NodeQuery) GroupBy(field string, fields ...string) *NodeGroupBy {
+	_q.ctx.Fields = append([]string{field}, fields...)
+	grbuild := &NodeGroupBy{build: _q}
+	grbuild.flds = &_q.ctx.Fields
+	grbuild.label = node.Label
+	grbuild.scan = grbuild.Scan
+	return grbuild
+}
+
+// Select allows the selection one or more fields/columns for the given query,
+// instead of selecting all fields in the entity.
+//
+// Example:
+//
+//	var v []struct {
+//		Value int `json:"value,omitempty"`
+//	}
+//
+//	client.Node.Query().
+//		Select(node.FieldValue).
+//		Scan(ctx, &v)
+func (_q *NodeQuery) Select(fields ...string) *NodeSelect {
+	_q.ctx.Fields = append(_q.ctx.Fields, fields...)
+	sbuild := &NodeSelect{NodeQuery: _q}
+	sbuild.label = node.Label
+	sbuild.flds, sbuild.scan = &_q.ctx.Fields, sbuild.Scan
+	return sbuild
+}
+
+// Aggregate returns a NodeSelect configured with the given aggregations.
+func (_q *NodeQuery) Aggregate(fns ...AggregateFunc) *NodeSelect {
+	return _q.Select().Aggregate(fns...)
+}
+
+func (_q *NodeQuery) prepareQuery(ctx context.Context) error {
+	for _, inter := range _q.inters {
+		if inter == nil {
+			return fmt.Errorf("ent: uninitialized interceptor (forgotten import ent/runtime?)")
+		}
+		if trv, ok := inter.(Traverser); ok {
+			if err := trv.Traverse(ctx, _q); err != nil {
+				return err
+			}
+		}
+	}
+	for _, f := range _q.ctx.Fields {
+		if !node.ValidColumn(f) {
+			return &ValidationError{Name: f, err: fmt.Errorf("ent: invalid field %q for query", f)}
+		}
+	}
+	if _q.path != nil {
+		prev, err := _q.path(ctx)
+		if err != nil {
+			return err
+		}
+		_q.sql = prev
+	}
+	return nil
+}
+
+func (_q *NodeQuery) sqlAll(ctx context.Context, hooks ...queryHook) ([]*Node, error) {
+	var (
+		nodes       = []*Node{}
+		_spec       = _q.querySpec()
+		loadedTypes = [2]bool{
+			_q.withPrev != nil,
+			_q.withNext != nil,
+		}
+	)
+	_spec.ScanValues = func(columns []string) ([]any, error) {
+		return (*Node).scanValues(nil, columns)
+	}
+	_spec.Assign = func(columns []string, values []any) error {
+		node := &Node{config: _q.config}
+		nodes = append(nodes, node)
+		node.Edges.loadedTypes = loadedTypes
+		return node.assignValues(columns, values)
+	}
+	for i := range hooks {
+		hooks[i](ctx, _spec)
+	}
+	if err := sqlgraph.QueryNodes(ctx, _q.driver, _spec); err != nil {
+		return nil, err
+	}
+	if len(nodes) == 0 {
+		return nodes, nil
+	}
+	if query := _q.withPrev; query != nil {
+		if err := _q.loadPrev(ctx, query, nodes, nil,
+			func(n *Node, e *Node) { n.Edges.Prev = e }); err != nil {
+			return nil, err
+		}
+	}
+	if query := _q.withNext; query != nil {
+		if err := _q.loadNext(ctx, query, nodes, nil,
+			func(n *Node, e *Node) { n.Edges.Next = e }); err != nil {
+			return nil, err
+		}
+	}
+	return nodes, nil
+}
+
+func (_q *NodeQuery) loadPrev(ctx context.Context, query *NodeQuery, nodes []*Node, init func(*Node), assign func(*Node, *Node)) error {
+	ids := make([]int, 0, len(nodes))
+	nodeids := make(map[int][]*Node)
+	for i := range nodes {
+		fk := nodes[i].PrevID
+		if _, ok := nodeids[fk]; !ok {
+			ids = append(ids, fk)
+		}
+		nodeids[fk] = append(nodeids[fk], nodes[i])
+	}
+	if len(ids) == 0 {
+		return nil
+	}
+	query.Where(node.IDIn(ids...))
+	neighbors, err := query.All(ctx)
+	if err != nil {
+		return err
+	}
+	for _, n := range neighbors {
+		nodes, ok := nodeids[n.ID]
+		if !ok {
+			return fmt.Errorf(`unexpected foreign-key "prev_id" returned %v`, n.ID)
+		}
+		for i := range nodes {
+			assign(nodes[i], n)
+		}
+	}
+	return nil
+}
+func (_q *NodeQuery) loadNext(ctx context.Context, query *NodeQuery, nodes []*Node, init func(*Node), assign func(*Node, *Node)) error {
+	fks := make([]driver.Value, 0, len(nodes))
+	nodeids := make(map[int]*Node)
+	for i := range nodes {
+		fks = append(fks, nodes[i].ID)
+		nodeids[nodes[i].ID] = nodes[i]
+	}
+	if len(query.ctx.Fields) > 0 {
+		query.ctx.AppendFieldOnce(node.FieldPrevID)
+	}
+	query.Where(predicate.Node(func(s *sql.Selector) {
+		s.Where(sql.InValues(s.C(node.NextColumn), fks...))
+	}))
+	neighbors, err := query.All(ctx)
+	if err != nil {
+		return err
+	}
+	for _, n := range neighbors {
+		fk := n.PrevID
+		node, ok := nodeids[fk]
+		if !ok {
+			return fmt.Errorf(`unexpected referenced foreign-key "prev_id" returned %v for node %v`, fk, n.ID)
+		}
+		assign(node, n)
+	}
+	return nil
+}
+
+func (_q *NodeQuery) sqlCount(ctx context.Context) (int, error) {
+	_spec := _q.querySpec()
+	_spec.Node.Columns = _q.ctx.Fields
+	if len(_q.ctx.Fields) > 0 {
+		_spec.Unique = _q.ctx.Unique != nil && *_q.ctx.Unique
+	}
+	return sqlgraph.CountNodes(ctx, _q.driver, _spec)
+}
+
+func (_q *NodeQuery) querySpec() *sqlgraph.QuerySpec {
+	_spec := sqlgraph.NewQuerySpec(node.Table, node.Columns, sqlgraph.NewFieldSpec(node.FieldID, field.TypeInt))
+	_spec.From = _q.sql
+	if unique := _q.ctx.Unique; unique != nil {
+		_spec.Unique = *unique
+	} else if _q.path != nil {
+		_spec.Unique = true
+	}
+	if fields := _q.ctx.Fields; len(fields) > 0 {
+		_spec.Node.Columns = make([]string, 0, len(fields))
+		_spec.Node.Columns = append(_spec.Node.Columns, node.FieldID)
+		for i := range fields {
+			if fields[i] != node.FieldID {
+				_spec.Node.Columns = append(_spec.Node.Columns, fields[i])
+			}
+		}
+		if _q.withPrev != nil {
+			_spec.Node.AddColumnOnce(node.FieldPrevID)
+		}
+	}
+	if ps := _q.predicates; len(ps) > 0 {
+		_spec.Predicate = func(selector *sql.Selector) {
+			for i := range ps {
+				ps[i](selector)
+			}
+		}
+	}
+	if limit := _q.ctx.Limit; limit != nil {
+		_spec.Limit = *limit
+	}
+	if offset := _q.ctx.Offset; offset != nil {
+		_spec.Offset = *offset
+	}
+	if ps := _q.order; len(ps) > 0 {
+		_spec.Order = func(selector *sql.Selector) {
+			for i := range ps {
+				ps[i](selector)
+			}
+		}
+	}
+	return _spec
+}
+
+func (_q *NodeQuery) sqlQuery(ctx context.Context) *sql.Selector {
+	builder := sql.Dialect(_q.driver.Dialect())
+	t1 := builder.Table(node.Table)
+	columns := _q.ctx.Fields
+	if len(columns) == 0 {
+		columns = node.Columns
+	}
+	selector := builder.Select(t1.Columns(columns...)...).From(t1)
+	if _q.sql != nil {
+		selector = _q.sql
+		selector.Select(selector.Columns(columns...)...)
+	}
+	if _q.ctx.Unique != nil && *_q.ctx.Unique {
+		selector.Distinct()
+	}
+	for _, p := range _q.predicates {
+		p(selector)
+	}
+	for _, p := range _q.order {
+		p(selector)
+	}
+	if offset := _q.ctx.Offset; offset != nil {
+		// limit is mandatory for offset clause. We start
+		// with default value, and override it below if needed.
+		selector.Offset(*offset).Limit(math.MaxInt32)
+	}
+	if limit := _q.ctx.Limit; limit != nil {
+		selector.Limit(*limit)
+	}
+	return selector
+}
+
+// NodeGroupBy is the group-by builder for Node entities.
+type NodeGroupBy struct {
+	selector
+	build *NodeQuery
+}
+
+// Aggregate adds the given aggregation functions to the group-by query.
+func (_g *NodeGroupBy) Aggregate(fns ...AggregateFunc) *NodeGroupBy {
+	_g.fns = append(_g.fns, fns...)
+	return _g
+}
+
+// Scan applies the selector query and scans the result into the given value.
+func (_g *NodeGroupBy) Scan(ctx context.Context, v any) error {
+	ctx = setContextOp(ctx, _g.build.ctx, ent.OpQueryGroupBy)
+	if err := _g.build.prepareQuery(ctx); err != nil {
+		return err
+	}
+	return scanWithInterceptors[*NodeQuery, *NodeGroupBy](ctx, _g.build, _g, _g.build.inters, v)
+}
+
+func (_g *NodeGroupBy) sqlScan(ctx context.Context, root *NodeQuery, v any) error {
+	selector := root.sqlQuery(ctx).Select()
+	aggregation := make([]string, 0, len(_g.fns))
+	for _, fn := range _g.fns {
+		aggregation = append(aggregation, fn(selector))
+	}
+	if len(selector.SelectedColumns()) == 0 {
+		columns := make([]string, 0, len(*_g.flds)+len(_g.fns))
+		for _, f := range *_g.flds {
+			columns = append(columns, selector.C(f))
+		}
+		columns = append(columns, aggregation...)
+		selector.Select(columns...)
+	}
+	selector.GroupBy(selector.Columns(*_g.flds...)...)
+	if err := selector.Err(); err != nil {
+		return err
+	}
+	rows := &sql.Rows{}
+	query, args := selector.Query()
+	if err := _g.build.driver.Query(ctx, query, args, rows); err != nil {
+		return err
+	}
+	defer rows.Close()
+	return sql.ScanSlice(rows, v)
+}
+
+// NodeSelect is the builder for selecting fields of Node entities.
+type NodeSelect struct {
+	*NodeQuery
+	selector
+}
+
+// Aggregate adds the given aggregation functions to the selector query.
+func (_s *NodeSelect) Aggregate(fns ...AggregateFunc) *NodeSelect {
+	_s.fns = append(_s.fns, fns...)
+	return _s
+}
+
+// Scan applies the selector query and scans the result into the given value.
+func (_s *NodeSelect) Scan(ctx context.Context, v any) error {
+	ctx = setContextOp(ctx, _s.ctx, ent.OpQuerySelect)
+	if err := _s.prepareQuery(ctx); err != nil {
+		return err
+	}
+	return scanWithInterceptors[*NodeQuery, *NodeSelect](ctx, _s.NodeQuery, _s, _s.inters, v)
+}
+
+func (_s *NodeSelect) sqlScan(ctx context.Context, root *NodeQuery, v any) error {
+	selector := root.sqlQuery(ctx)
+	aggregation := make([]string, 0, len(_s.fns))
+	for _, fn := range _s.fns {
+		aggregation = append(aggregation, fn(selector))
+	}
+	switch n := len(*_s.selector.flds); {
+	case n == 0 && len(aggregation) > 0:
+		selector.Select(aggregation...)
+	case n != 0 && len(aggregation) > 0:
+		selector.AppendSelect(aggregation...)
+	}
+	rows := &sql.Rows{}
+	query, args := selector.Query()
+	if err := _s.driver.Query(ctx, query, args, rows); err != nil {
+		return err
+	}
+	defer rows.Close()
+	return sql.ScanSlice(rows, v)
+}

examples/o2orecur/ent/node_update.go

@@ -0,0 +1,461 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated by ent, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"entgo.io/ent/dialect/sql"
+	"entgo.io/ent/dialect/sql/sqlgraph"
+	"entgo.io/ent/examples/o2orecur/ent/node"
+	"entgo.io/ent/examples/o2orecur/ent/predicate"
+	"entgo.io/ent/schema/field"
+)
+
+// NodeUpdate is the builder for updating Node entities.
+type NodeUpdate struct {
+	config
+	hooks    []Hook
+	mutation *NodeMutation
+}
+
+// Where appends a list predicates to the NodeUpdate builder.
+func (_u *NodeUpdate) Where(ps ...predicate.Node) *NodeUpdate {
+	_u.mutation.Where(ps...)
+	return _u
+}
+
+// SetValue sets the "value" field.
+func (_u *NodeUpdate) SetValue(v int) *NodeUpdate {
+	_u.mutation.ResetValue()
+	_u.mutation.SetValue(v)
+	return _u
+}
+
+// SetNillableValue sets the "value" field if the given value is not nil.
+func (_u *NodeUpdate) SetNillableValue(v *int) *NodeUpdate {
+	if v != nil {
+		_u.SetValue(*v)
+	}
+	return _u
+}
+
+// AddValue adds value to the "value" field.
+func (_u *NodeUpdate) AddValue(v int) *NodeUpdate {
+	_u.mutation.AddValue(v)
+	return _u
+}
+
+// SetPrevID sets the "prev_id" field.
+func (_u *NodeUpdate) SetPrevID(v int) *NodeUpdate {
+	_u.mutation.SetPrevID(v)
+	return _u
+}
+
+// SetNillablePrevID sets the "prev_id" field if the given value is not nil.
+func (_u *NodeUpdate) SetNillablePrevID(v *int) *NodeUpdate {
+	if v != nil {
+		_u.SetPrevID(*v)
+	}
+	return _u
+}
+
+// ClearPrevID clears the value of the "prev_id" field.
+func (_u *NodeUpdate) ClearPrevID() *NodeUpdate {
+	_u.mutation.ClearPrevID()
+	return _u
+}
+
+// SetPrev sets the "prev" edge to the Node entity.
+func (_u *NodeUpdate) SetPrev(v *Node) *NodeUpdate {
+	return _u.SetPrevID(v.ID)
+}
+
+// SetNextID sets the "next" edge to the Node entity by ID.
+func (_u *NodeUpdate) SetNextID(id int) *NodeUpdate {
+	_u.mutation.SetNextID(id)
+	return _u
+}
+
+// SetNillableNextID sets the "next" edge to the Node entity by ID if the given value is not nil.
+func (_u *NodeUpdate) SetNillableNextID(id *int) *NodeUpdate {
+	if id != nil {
+		_u = _u.SetNextID(*id)
+	}
+	return _u
+}
+
+// SetNext sets the "next" edge to the Node entity.
+func (_u *NodeUpdate) SetNext(v *Node) *NodeUpdate {
+	return _u.SetNextID(v.ID)
+}
+
+// Mutation returns the NodeMutation object of the builder.
+func (_u *NodeUpdate) Mutation() *NodeMutation {
+	return _u.mutation
+}
+
+// ClearPrev clears the "prev" edge to the Node entity.
+func (_u *NodeUpdate) ClearPrev() *NodeUpdate {
+	_u.mutation.ClearPrev()
+	return _u
+}
+
+// ClearNext clears the "next" edge to the Node entity.
+func (_u *NodeUpdate) ClearNext() *NodeUpdate {
+	_u.mutation.ClearNext()
+	return _u
+}
+
+// Save executes the query and returns the number of nodes affected by the update operation.
+func (_u *NodeUpdate) Save(ctx context.Context) (int, error) {
+	return withHooks(ctx, _u.sqlSave, _u.mutation, _u.hooks)
+}
+
+// SaveX is like Save, but panics if an error occurs.
+func (_u *NodeUpdate) SaveX(ctx context.Context) int {
+	affected, err := _u.Save(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return affected
+}
+
+// Exec executes the query.
+func (_u *NodeUpdate) Exec(ctx context.Context) error {
+	_, err := _u.Save(ctx)
+	return err
+}
+
+// ExecX is like Exec, but panics if an error occurs.
+func (_u *NodeUpdate) ExecX(ctx context.Context) {
+	if err := _u.Exec(ctx); err != nil {
+		panic(err)
+	}
+}
+
+func (_u *NodeUpdate) sqlSave(ctx context.Context) (_node int, err error) {
+	_spec := sqlgraph.NewUpdateSpec(node.Table, node.Columns, sqlgraph.NewFieldSpec(node.FieldID, field.TypeInt))
+	if ps := _u.mutation.Predicates(); len(ps) > 0 {
+		_spec.Predicate = func(selector *sql.Selector) {
+			for i := range ps {
+				ps[i](selector)
+			}
+		}
+	}
+	if value, ok := _u.mutation.Value(); ok {
+		_spec.SetField(node.FieldValue, field.TypeInt, value)
+	}
+	if value, ok := _u.mutation.AddedValue(); ok {
+		_spec.AddField(node.FieldValue, field.TypeInt, value)
+	}
+	if _u.mutation.PrevCleared() {
+		edge := &sqlgraph.EdgeSpec{
+			Rel:     sqlgraph.O2O,
+			Inverse: true,
+			Table:   node.PrevTable,
+			Columns: []string{node.PrevColumn},
+			Bidi:    false,
+			Target: &sqlgraph.EdgeTarget{
+				IDSpec: sqlgraph.NewFieldSpec(node.FieldID, field.TypeInt),
+			},
+		}
+		_spec.Edges.Clear = append(_spec.Edges.Clear, edge)
+	}
+	if nodes := _u.mutation.PrevIDs(); len(nodes) > 0 {
+		edge := &sqlgraph.EdgeSpec{
+			Rel:     sqlgraph.O2O,
+			Inverse: true,
+			Table:   node.PrevTable,
+			Columns: []string{node.PrevColumn},
+			Bidi:    false,
+			Target: &sqlgraph.EdgeTarget{
+				IDSpec: sqlgraph.NewFieldSpec(node.FieldID, field.TypeInt),
+			},
+		}
+		for _, k := range nodes {
+			edge.Target.Nodes = append(edge.Target.Nodes, k)
+		}
+		_spec.Edges.Add = append(_spec.Edges.Add, edge)
+	}
+	if _u.mutation.NextCleared() {
+		edge := &sqlgraph.EdgeSpec{
+			Rel:     sqlgraph.O2O,
+			Inverse: false,
+			Table:   node.NextTable,
+			Columns: []string{node.NextColumn},
+			Bidi:    false,
+			Target: &sqlgraph.EdgeTarget{
+				IDSpec: sqlgraph.NewFieldSpec(node.FieldID, field.TypeInt),
+			},
+		}
+		_spec.Edges.Clear = append(_spec.Edges.Clear, edge)
+	}
+	if nodes := _u.mutation.NextIDs(); len(nodes) > 0 {
+		edge := &sqlgraph.EdgeSpec{
+			Rel:     sqlgraph.O2O,
+			Inverse: false,
+			Table:   node.NextTable,
+			Columns: []string{node.NextColumn},
+			Bidi:    false,
+			Target: &sqlgraph.EdgeTarget{
+				IDSpec: sqlgraph.NewFieldSpec(node.FieldID, field.TypeInt),
+			},
+		}
+		for _, k := range nodes {
+			edge.Target.Nodes = append(edge.Target.Nodes, k)
+		}
+		_spec.Edges.Add = append(_spec.Edges.Add, edge)
+	}
+	if _node, err = sqlgraph.UpdateNodes(ctx, _u.driver, _spec); err != nil {
+		if _, ok := err.(*sqlgraph.NotFoundError); ok {
+			err = &NotFoundError{node.Label}
+		} else if sqlgraph.IsConstraintError(err) {
+			err = &ConstraintError{msg: err.Error(), wrap: err}
+		}
+		return 0, err
+	}
+	_u.mutation.done = true
+	return _node, nil
+}
+
+// NodeUpdateOne is the builder for updating a single Node entity.
+type NodeUpdateOne struct {
+	config
+	fields   []string
+	hooks    []Hook
+	mutation *NodeMutation
+}
+
+// SetValue sets the "value" field.
+func (_u *NodeUpdateOne) SetValue(v int) *NodeUpdateOne {
+	_u.mutation.ResetValue()
+	_u.mutation.SetValue(v)
+	return _u
+}
+
+// SetNillableValue sets the "value" field if the given value is not nil.
+func (_u *NodeUpdateOne) SetNillableValue(v *int) *NodeUpdateOne {
+	if v != nil {
+		_u.SetValue(*v)
+	}
+	return _u
+}
+
+// AddValue adds value to the "value" field.
+func (_u *NodeUpdateOne) AddValue(v int) *NodeUpdateOne {
+	_u.mutation.AddValue(v)
+	return _u
+}
+
+// SetPrevID sets the "prev_id" field.
+func (_u *NodeUpdateOne) SetPrevID(v int) *NodeUpdateOne {
+	_u.mutation.SetPrevID(v)
+	return _u
+}
+
+// SetNillablePrevID sets the "prev_id" field if the given value is not nil.
+func (_u *NodeUpdateOne) SetNillablePrevID(v *int) *NodeUpdateOne {
+	if v != nil {
+		_u.SetPrevID(*v)
+	}
+	return _u
+}
+
+// ClearPrevID clears the value of the "prev_id" field.
+func (_u *NodeUpdateOne) ClearPrevID() *NodeUpdateOne {
+	_u.mutation.ClearPrevID()
+	return _u
+}
+
+// SetPrev sets the "prev" edge to the Node entity.
+func (_u *NodeUpdateOne) SetPrev(v *Node) *NodeUpdateOne {
+	return _u.SetPrevID(v.ID)
+}
+
+// SetNextID sets the "next" edge to the Node entity by ID.
+func (_u *NodeUpdateOne) SetNextID(id int) *NodeUpdateOne {
+	_u.mutation.SetNextID(id)
+	return _u
+}
+
+// SetNillableNextID sets the "next" edge to the Node entity by ID if the given value is not nil.
+func (_u *NodeUpdateOne) SetNillableNextID(id *int) *NodeUpdateOne {
+	if id != nil {
+		_u = _u.SetNextID(*id)
+	}
+	return _u
+}
+
+// SetNext sets the "next" edge to the Node entity.
+func (_u *NodeUpdateOne) SetNext(v *Node) *NodeUpdateOne {
+	return _u.SetNextID(v.ID)
+}
+
+// Mutation returns the NodeMutation object of the builder.
+func (_u *NodeUpdateOne) Mutation() *NodeMutation {
+	return _u.mutation
+}
+
+// ClearPrev clears the "prev" edge to the Node entity.
+func (_u *NodeUpdateOne) ClearPrev() *NodeUpdateOne {
+	_u.mutation.ClearPrev()
+	return _u
+}
+
+// ClearNext clears the "next" edge to the Node entity.
+func (_u *NodeUpdateOne) ClearNext() *NodeUpdateOne {
+	_u.mutation.ClearNext()
+	return _u
+}
+
+// Where appends a list predicates to the NodeUpdate builder.
+func (_u *NodeUpdateOne) Where(ps ...predicate.Node) *NodeUpdateOne {
+	_u.mutation.Where(ps...)
+	return _u
+}
+
+// Select allows selecting one or more fields (columns) of the returned entity.
+// The default is selecting all fields defined in the entity schema.
+func (_u *NodeUpdateOne) Select(field string, fields ...string) *NodeUpdateOne {
+	_u.fields = append([]string{field}, fields...)
+	return _u
+}
+
+// Save executes the query and returns the updated Node entity.
+func (_u *NodeUpdateOne) Save(ctx context.Context) (*Node, error) {
+	return withHooks(ctx, _u.sqlSave, _u.mutation, _u.hooks)
+}
+
+// SaveX is like Save, but panics if an error occurs.
+func (_u *NodeUpdateOne) SaveX(ctx context.Context) *Node {
+	node, err := _u.Save(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return node
+}
+
+// Exec executes the query on the entity.
+func (_u *NodeUpdateOne) Exec(ctx context.Context) error {
+	_, err := _u.Save(ctx)
+	return err
+}
+
+// ExecX is like Exec, but panics if an error occurs.
+func (_u *NodeUpdateOne) ExecX(ctx context.Context) {
+	if err := _u.Exec(ctx); err != nil {
+		panic(err)
+	}
+}
+
+func (_u *NodeUpdateOne) sqlSave(ctx context.Context) (_node *Node, err error) {
+	_spec := sqlgraph.NewUpdateSpec(node.Table, node.Columns, sqlgraph.NewFieldSpec(node.FieldID, field.TypeInt))
+	id, ok := _u.mutation.ID()
+	if !ok {
+		return nil, &ValidationError{Name: "id", err: errors.New(`ent: missing "Node.id" for update`)}
+	}
+	_spec.Node.ID.Value = id
+	if fields := _u.fields; len(fields) > 0 {
+		_spec.Node.Columns = make([]string, 0, len(fields))
+		_spec.Node.Columns = append(_spec.Node.Columns, node.FieldID)
+		for _, f := range fields {
+			if !node.ValidColumn(f) {
+				return nil, &ValidationError{Name: f, err: fmt.Errorf("ent: invalid field %q for query", f)}
+			}
+			if f != node.FieldID {
+				_spec.Node.Columns = append(_spec.Node.Columns, f)
+			}
+		}
+	}
+	if ps := _u.mutation.Predicates(); len(ps) > 0 {
+		_spec.Predicate = func(selector *sql.Selector) {
+			for i := range ps {
+				ps[i](selector)
+			}
+		}
+	}
+	if value, ok := _u.mutation.Value(); ok {
+		_spec.SetField(node.FieldValue, field.TypeInt, value)
+	}
+	if value, ok := _u.mutation.AddedValue(); ok {
+		_spec.AddField(node.FieldValue, field.TypeInt, value)
+	}
+	if _u.mutation.PrevCleared() {
+		edge := &sqlgraph.EdgeSpec{
+			Rel:     sqlgraph.O2O,
+			Inverse: true,
+			Table:   node.PrevTable,
+			Columns: []string{node.PrevColumn},
+			Bidi:    false,
+			Target: &sqlgraph.EdgeTarget{
+				IDSpec: sqlgraph.NewFieldSpec(node.FieldID, field.TypeInt),
+			},
+		}
+		_spec.Edges.Clear = append(_spec.Edges.Clear, edge)
+	}
+	if nodes := _u.mutation.PrevIDs(); len(nodes) > 0 {
+		edge := &sqlgraph.EdgeSpec{
+			Rel:     sqlgraph.O2O,
+			Inverse: true,
+			Table:   node.PrevTable,
+			Columns: []string{node.PrevColumn},
+			Bidi:    false,
+			Target: &sqlgraph.EdgeTarget{
+				IDSpec: sqlgraph.NewFieldSpec(node.FieldID, field.TypeInt),
+			},
+		}
+		for _, k := range nodes {
+			edge.Target.Nodes = append(edge.Target.Nodes, k)
+		}
+		_spec.Edges.Add = append(_spec.Edges.Add, edge)
+	}
+	if _u.mutation.NextCleared() {
+		edge := &sqlgraph.EdgeSpec{
+			Rel:     sqlgraph.O2O,
+			Inverse: false,
+			Table:   node.NextTable,
+			Columns: []string{node.NextColumn},
+			Bidi:    false,
+			Target: &sqlgraph.EdgeTarget{
+				IDSpec: sqlgraph.NewFieldSpec(node.FieldID, field.TypeInt),
+			},
+		}
+		_spec.Edges.Clear = append(_spec.Edges.Clear, edge)
+	}
+	if nodes := _u.mutation.NextIDs(); len(nodes) > 0 {
+		edge := &sqlgraph.EdgeSpec{
+			Rel:     sqlgraph.O2O,
+			Inverse: false,
+			Table:   node.NextTable,
+			Columns: []string{node.NextColumn},
+			Bidi:    false,
+			Target: &sqlgraph.EdgeTarget{
+				IDSpec: sqlgraph.NewFieldSpec(node.FieldID, field.TypeInt),
+			},
+		}
+		for _, k := range nodes {
+			edge.Target.Nodes = append(edge.Target.Nodes, k)
+		}
+		_spec.Edges.Add = append(_spec.Edges.Add, edge)
+	}
+	_node = &Node{config: _u.config}
+	_spec.Assign = _node.assignValues
+	_spec.ScanValues = _node.scanValues
+	if err = sqlgraph.UpdateNode(ctx, _u.driver, _spec); err != nil {
+		if _, ok := err.(*sqlgraph.NotFoundError); ok {
+			err = &NotFoundError{node.Label}
+		} else if sqlgraph.IsConstraintError(err) {
+			err = &ConstraintError{msg: err.Error(), wrap: err}
+		}
+		return nil, err
+	}
+	_u.mutation.done = true
+	return _node, nil
+}

examples/o2orecur/ent/predicate/predicate.go

@@ -0,0 +1,14 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated by ent, DO NOT EDIT.
+
+package predicate
+
+import (
+	"entgo.io/ent/dialect/sql"
+)
+
+// Node is the predicate function for node builders.
+type Node func(*sql.Selector)

examples/o2orecur/ent/runtime.go

@@ -0,0 +1,13 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated by ent, DO NOT EDIT.
+
+package ent
+
+// The init function reads all schema descriptors with runtime code
+// (default values, validators, hooks and policies) and stitches it
+// to their package variables.
+func init() {
+}

examples/o2orecur/ent/runtime/runtime.go

@@ -0,0 +1,13 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated by ent, DO NOT EDIT.
+
+package runtime
+
+// The schema-stitching logic is generated in entgo.io/ent/examples/o2orecur/ent/runtime.go
+
+const (
+	Version = "v0.0.0-00010101000000-000000000000" // Version of ent codegen.
+)

examples/o2orecur/ent/schema/node.go

@@ -0,0 +1,36 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+package schema
+
+import (
+	"entgo.io/ent"
+	"entgo.io/ent/schema/edge"
+	"entgo.io/ent/schema/field"
+)
+
+// Node holds the schema definition for the Node entity.
+type Node struct {
+	ent.Schema
+}
+
+// Fields of the Node.
+func (Node) Fields() []ent.Field {
+	return []ent.Field{
+		field.Int("value"),
+		field.Int("prev_id").
+			Optional(),
+	}
+}
+
+// Edges of the Node.
+func (Node) Edges() []ent.Edge {
+	return []ent.Edge{
+		edge.To("next", Node.Type).
+			Unique().
+			From("prev").
+			Field("prev_id").
+			Unique(),
+	}
+}

examples/o2orecur/ent/tx.go

@@ -0,0 +1,214 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated by ent, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+	"sync"
+
+	"entgo.io/ent/dialect"
+)
+
+// Tx is a transactional client that is created by calling Client.Tx().
+type Tx struct {
+	config
+	// Node is the client for interacting with the Node builders.
+	Node *NodeClient
+
+	// lazily loaded.
+	client     *Client
+	clientOnce sync.Once
+	// ctx lives for the life of the transaction. It is
+	// the same context used by the underlying connection.
+	ctx context.Context
+}
+
+type (
+	// Committer is the interface that wraps the Commit method.
+	Committer interface {
+		Commit(context.Context, *Tx) error
+	}
+
+	// The CommitFunc type is an adapter to allow the use of ordinary
+	// function as a Committer. If f is a function with the appropriate
+	// signature, CommitFunc(f) is a Committer that calls f.
+	CommitFunc func(context.Context, *Tx) error
+
+	// CommitHook defines the "commit middleware". A function that gets a Committer
+	// and returns a Committer. For example:
+	//
+	//	hook := func(next ent.Committer) ent.Committer {
+	//		return ent.CommitFunc(func(ctx context.Context, tx *ent.Tx) error {
+	//			// Do some stuff before.
+	//			if err := next.Commit(ctx, tx); err != nil {
+	//				return err
+	//			}
+	//			// Do some stuff after.
+	//			return nil
+	//		})
+	//	}
+	//
+	CommitHook func(Committer) Committer
+)
+
+// Commit calls f(ctx, m).
+func (f CommitFunc) Commit(ctx context.Context, tx *Tx) error {
+	return f(ctx, tx)
+}
+
+// Commit commits the transaction.
+func (tx *Tx) Commit() error {
+	txDriver := tx.config.driver.(*txDriver)
+	var fn Committer = CommitFunc(func(context.Context, *Tx) error {
+		return txDriver.tx.Commit()
+	})
+	txDriver.mu.Lock()
+	hooks := append([]CommitHook(nil), txDriver.onCommit...)
+	txDriver.mu.Unlock()
+	for i := len(hooks) - 1; i >= 0; i-- {
+		fn = hooks[i](fn)
+	}
+	return fn.Commit(tx.ctx, tx)
+}
+
+// OnCommit adds a hook to call on commit.
+func (tx *Tx) OnCommit(f CommitHook) {
+	txDriver := tx.config.driver.(*txDriver)
+	txDriver.mu.Lock()
+	txDriver.onCommit = append(txDriver.onCommit, f)
+	txDriver.mu.Unlock()
+}
+
+type (
+	// Rollbacker is the interface that wraps the Rollback method.
+	Rollbacker interface {
+		Rollback(context.Context, *Tx) error
+	}
+
+	// The RollbackFunc type is an adapter to allow the use of ordinary
+	// function as a Rollbacker. If f is a function with the appropriate
+	// signature, RollbackFunc(f) is a Rollbacker that calls f.
+	RollbackFunc func(context.Context, *Tx) error
+
+	// RollbackHook defines the "rollback middleware". A function that gets a Rollbacker
+	// and returns a Rollbacker. For example:
+	//
+	//	hook := func(next ent.Rollbacker) ent.Rollbacker {
+	//		return ent.RollbackFunc(func(ctx context.Context, tx *ent.Tx) error {
+	//			// Do some stuff before.
+	//			if err := next.Rollback(ctx, tx); err != nil {
+	//				return err
+	//			}
+	//			// Do some stuff after.
+	//			return nil
+	//		})
+	//	}
+	//
+	RollbackHook func(Rollbacker) Rollbacker
+)
+
+// Rollback calls f(ctx, m).
+func (f RollbackFunc) Rollback(ctx context.Context, tx *Tx) error {
+	return f(ctx, tx)
+}
+
+// Rollback rollbacks the transaction.
+func (tx *Tx) Rollback() error {
+	txDriver := tx.config.driver.(*txDriver)
+	var fn Rollbacker = RollbackFunc(func(context.Context, *Tx) error {
+		return txDriver.tx.Rollback()
+	})
+	txDriver.mu.Lock()
+	hooks := append([]RollbackHook(nil), txDriver.onRollback...)
+	txDriver.mu.Unlock()
+	for i := len(hooks) - 1; i >= 0; i-- {
+		fn = hooks[i](fn)
+	}
+	return fn.Rollback(tx.ctx, tx)
+}
+
+// OnRollback adds a hook to call on rollback.
+func (tx *Tx) OnRollback(f RollbackHook) {
+	txDriver := tx.config.driver.(*txDriver)
+	txDriver.mu.Lock()
+	txDriver.onRollback = append(txDriver.onRollback, f)
+	txDriver.mu.Unlock()
+}
+
+// Client returns a Client that binds to current transaction.
+func (tx *Tx) Client() *Client {
+	tx.clientOnce.Do(func() {
+		tx.client = &Client{config: tx.config}
+		tx.client.init()
+	})
+	return tx.client
+}
+
+func (tx *Tx) init() {
+	tx.Node = NewNodeClient(tx.config)
+}
+
+// txDriver wraps the given dialect.Tx with a nop dialect.Driver implementation.
+// The idea is to support transactions without adding any extra code to the builders.
+// When a builder calls to driver.Tx(), it gets the same dialect.Tx instance.
+// Commit and Rollback are nop for the internal builders and the user must call one
+// of them in order to commit or rollback the transaction.
+//
+// If a closed transaction is embedded in one of the generated entities, and the entity
+// applies a query, for example: Node.QueryXXX(), the query will be executed
+// through the driver which created this transaction.
+//
+// Note that txDriver is not goroutine safe.
+type txDriver struct {
+	// the driver we started the transaction from.
+	drv dialect.Driver
+	// tx is the underlying transaction.
+	tx dialect.Tx
+	// completion hooks.
+	mu         sync.Mutex
+	onCommit   []CommitHook
+	onRollback []RollbackHook
+}
+
+// newTx creates a new transactional driver.
+func newTx(ctx context.Context, drv dialect.Driver) (*txDriver, error) {
+	tx, err := drv.Tx(ctx)
+	if err != nil {
+		return nil, err
+	}
+	return &txDriver{tx: tx, drv: drv}, nil
+}
+
+// Tx returns the transaction wrapper (txDriver) to avoid Commit or Rollback calls
+// from the internal builders. Should be called only by the internal builders.
+func (tx *txDriver) Tx(context.Context) (dialect.Tx, error) { return tx, nil }
+
+// Dialect returns the dialect of the driver we started the transaction from.
+func (tx *txDriver) Dialect() string { return tx.drv.Dialect() }
+
+// Close is a nop close.
+func (*txDriver) Close() error { return nil }
+
+// Commit is a nop commit for the internal builders.
+// User must call `Tx.Commit` in order to commit the transaction.
+func (*txDriver) Commit() error { return nil }
+
+// Rollback is a nop rollback for the internal builders.
+// User must call `Tx.Rollback` in order to rollback the transaction.
+func (*txDriver) Rollback() error { return nil }
+
+// Exec calls tx.Exec.
+func (tx *txDriver) Exec(ctx context.Context, query string, args, v any) error {
+	return tx.tx.Exec(ctx, query, args, v)
+}
+
+// Query calls tx.Query.
+func (tx *txDriver) Query(ctx context.Context, query string, args, v any) error {
+	return tx.tx.Query(ctx, query, args, v)
+}
+
+var _ dialect.Driver = (*txDriver)(nil)