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

examples/start/start.go

@@ -0,0 +1,282 @@
+// 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 main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"time"
+
+	"entgo.io/ent/examples/start/ent"
+	"entgo.io/ent/examples/start/ent/car"
+	"entgo.io/ent/examples/start/ent/group"
+	"entgo.io/ent/examples/start/ent/user"
+
+	_ "github.com/mattn/go-sqlite3"
+)
+
+func main() {
+	client, err := ent.Open("sqlite3", "file:ent?mode=memory&cache=shared&_fk=1")
+	if err != nil {
+		log.Fatalf("failed opening connection to sqlite: %v", err)
+	}
+	defer client.Close()
+	ctx := context.Background()
+	// Run the auto migration tool.
+	if err := client.Schema.Create(ctx); err != nil {
+		log.Fatalf("failed creating schema resources: %v", err)
+	}
+	if _, err = CreateUser(ctx, client); err != nil {
+		log.Fatal(err)
+	}
+	if _, err = QueryUser(ctx, client); err != nil {
+		log.Fatal(err)
+	}
+	a8m, err := CreateCars(ctx, client)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if err := QueryCars(ctx, a8m); err != nil {
+		log.Fatal(err)
+	}
+	if err := QueryCarUsers(ctx, a8m); err != nil {
+		log.Fatal(err)
+	}
+	if err := CreateGraph(ctx, client); err != nil {
+		log.Fatal(err)
+	}
+	if err := QueryGithub(ctx, client); err != nil {
+		log.Fatal(err)
+	}
+	if err := QueryArielCars(ctx, client); err != nil {
+		log.Fatal(err)
+	}
+	if err := QueryGroupWithUsers(ctx, client); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func CreateUser(ctx context.Context, client *ent.Client) (*ent.User, error) {
+	u, err := client.User.
+		Create().
+		SetAge(30).
+		SetName("a8m").
+		Save(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("failed creating user: %w", err)
+	}
+	log.Println("user was created: ", u)
+	return u, nil
+}
+
+func QueryUser(ctx context.Context, client *ent.Client) (*ent.User, error) {
+	u, err := client.User.
+		Query().
+		Where(user.NameEQ("a8m")).
+		// `Only` fails if no user found,
+		// or more than 1 user returned.
+		Only(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("failed querying user: %w", err)
+	}
+	log.Println("user returned: ", u)
+	return u, nil
+}
+
+func CreateCars(ctx context.Context, client *ent.Client) (*ent.User, error) {
+	// Create a new car with model "Tesla".
+	tesla, err := client.Car.
+		Create().
+		SetModel("Tesla").
+		SetRegisteredAt(time.Now()).
+		Save(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("failed creating car: %w", err)
+	}
+
+	// Create a new car with model "Ford".
+	ford, err := client.Car.
+		Create().
+		SetModel("Ford").
+		SetRegisteredAt(time.Now()).
+		Save(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("failed creating car: %w", err)
+	}
+	log.Println("car was created: ", ford)
+
+	// Create a new user, and add it the 2 cars.
+	a8m, err := client.User.
+		Create().
+		SetAge(30).
+		SetName("a8m").
+		AddCars(tesla, ford).
+		Save(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("failed creating user: %w", err)
+	}
+	log.Println("user was created: ", a8m)
+	return a8m, nil
+}
+
+func QueryCars(ctx context.Context, a8m *ent.User) error {
+	cars, err := a8m.QueryCars().All(ctx)
+	if err != nil {
+		return fmt.Errorf("failed querying user cars: %w", err)
+	}
+	log.Println("returned cars:", cars)
+
+	// What about filtering specific cars.
+	ford, err := a8m.QueryCars().
+		Where(car.ModelEQ("Ford")).
+		Only(ctx)
+	if err != nil {
+		return fmt.Errorf("failed querying user cars: %w", err)
+	}
+	log.Println(ford)
+	return nil
+}
+
+func QueryCarUsers(ctx context.Context, a8m *ent.User) error {
+	cars, err := a8m.QueryCars().All(ctx)
+	if err != nil {
+		return fmt.Errorf("failed querying user cars: %w", err)
+	}
+
+	// Query the inverse edge.
+	for _, c := range cars {
+		owner, err := c.QueryOwner().Only(ctx)
+		if err != nil {
+			return fmt.Errorf("failed querying car %q owner: %w", c.Model, err)
+		}
+		log.Printf("car %q owner: %q\n", c.Model, owner.Name)
+	}
+	return nil
+}
+
+func CreateGraph(ctx context.Context, client *ent.Client) error {
+	// First, create the users.
+	a8m, err := client.User.
+		Create().
+		SetAge(30).
+		SetName("Ariel").
+		Save(ctx)
+	if err != nil {
+		return err
+	}
+	neta, err := client.User.
+		Create().
+		SetAge(28).
+		SetName("Neta").
+		Save(ctx)
+	if err != nil {
+		return err
+	}
+	// Then, create the cars, and attach them to the users created above.
+	err = client.Car.
+		Create().
+		SetModel("Tesla").
+		SetRegisteredAt(time.Now()).
+		// Attach this car to Ariel.
+		SetOwner(a8m).
+		Exec(ctx)
+	if err != nil {
+		return err
+	}
+	err = client.Car.
+		Create().
+		SetModel("Mazda").
+		SetRegisteredAt(time.Now()).
+		// Attach this car to Ariel.
+		SetOwner(a8m).
+		Exec(ctx)
+	if err != nil {
+		return err
+	}
+	err = client.Car.
+		Create().
+		SetModel("Ford").
+		SetRegisteredAt(time.Now()).
+		// Attach this car to Neta.
+		SetOwner(neta).
+		Exec(ctx)
+	if err != nil {
+		return err
+	}
+	// Create the groups, and add their users in the creation.
+	err = client.Group.
+		Create().
+		SetName("GitLab").
+		AddUsers(neta, a8m).
+		Exec(ctx)
+	if err != nil {
+		return err
+	}
+	err = client.Group.
+		Create().
+		SetName("GitHub").
+		AddUsers(a8m).
+		Exec(ctx)
+	if err != nil {
+		return err
+	}
+	log.Println("The graph was created successfully")
+	return nil
+}
+
+func QueryGithub(ctx context.Context, client *ent.Client) error {
+	cars, err := client.Group.
+		Query().
+		Where(group.Name("GitHub")). // (Group(Name=GitHub),)
+		QueryUsers().                // (User(Name=Ariel, Age=30),)
+		QueryCars().                 // (Car(Model=Tesla, RegisteredAt=<Time>), Car(Model=Mazda, RegisteredAt=<Time>),)
+		All(ctx)
+	if err != nil {
+		return fmt.Errorf("failed getting cars: %w", err)
+	}
+	log.Println("cars returned:", cars)
+	// Output: (Car(Model=Tesla, RegisteredAt=<Time>), Car(Model=Mazda, RegisteredAt=<Time>),)
+	return nil
+}
+
+func QueryArielCars(ctx context.Context, client *ent.Client) error {
+	// Get "Ariel" from previous steps.
+	a8m := client.User.
+		Query().
+		Where(
+			user.HasCars(),
+			user.Name("Ariel"),
+		).
+		OnlyX(ctx)
+	cars, err := a8m. // Get the groups, that a8m is connected to:
+				QueryGroups(). // (Group(Name=GitHub), Group(Name=GitLab),)
+				QueryUsers().  // (User(Name=Ariel, Age=30), User(Name=Neta, Age=28),)
+				QueryCars().   //
+				Where(         //
+			car.Not( //	Get Neta and Ariel cars, but filter out
+				car.ModelEQ("Mazda"), //	those who named "Mazda"
+			), //
+		). //
+		All(ctx)
+	if err != nil {
+		return fmt.Errorf("failed getting cars: %w", err)
+	}
+	log.Println("cars returned:", cars)
+	return nil
+}
+
+func QueryGroupWithUsers(ctx context.Context, client *ent.Client) error {
+	groups, err := client.Group.
+		Query().
+		Where(group.HasUsers()).
+		All(ctx)
+	if err != nil {
+		return fmt.Errorf("failed getting groups: %w", err)
+	}
+	log.Println("groups returned:", groups)
+	// Output: (Group(Name=GitHub), Group(Name=GitLab),)
+	return nil
+}