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61 lines
1.3 KiB
Markdown
61 lines
1.3 KiB
Markdown
# Embedding structs
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Embedding allows you to reuse existing model structs in more queries, resulting
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in less manual serialization work. First, imagine we have the following schema
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with students and test scores.
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```sql
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CREATE TABLE students (
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id bigserial PRIMARY KEY,
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name text NOT NULL,
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age integer NOT NULL
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);
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CREATE TABLE test_scores (
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student_id bigint NOT NULL,
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score integer NOT NULL,
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grade text NOT NULL
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);
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```
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We want to select the student record and the scores they got on a test.
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Here's how we'd usually do that:
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```sql
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-- name: ScoreAndTests :many
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SELECT students.*, test_scores.*
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FROM students
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JOIN test_scores ON test_scores.student_id = students.id
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WHERE students.id = $1;
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```
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When using Go, sqlc will produce a struct like this:
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```go
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type ScoreAndTestsRow struct {
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ID int64
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Name string
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Age int32
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StudentID int64
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Score int32
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Grade string
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}
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```
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With embedding, the struct will contain a model for both tables instead of a
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flattened list of columns.
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```sql
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-- name: ScoreAndTests :many
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SELECT sqlc.embed(students), sqlc.embed(test_scores)
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FROM students
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JOIN test_scores ON test_scores.student_id = students.id
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WHERE students.id = $1;
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```
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```
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type ScoreAndTestsRow struct {
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Student Student
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TestScore TestScore
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}
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``` |