You are viewing the documentation for v1.8.0, an older release of sqlc. View the latest documentation.

Getting started

Okay, enough hype, let’s see it in action.

First you pass the following SQL to sqlc generate:

CREATE TABLE authors (
  id   BIGSERIAL PRIMARY KEY,
  name text      NOT NULL,
  bio  text
);

-- name: GetAuthor :one
SELECT * FROM authors
WHERE id = $1 LIMIT 1;

-- name: ListAuthors :many
SELECT * FROM authors
ORDER BY name;

-- name: CreateAuthor :one
INSERT INTO authors (
  name, bio
) VALUES (
  $1, $2
)
RETURNING *;

-- name: DeleteAuthor :exec
DELETE FROM authors
WHERE id = $1;

And then in your application code you’d write:

// list all authors
authors, err := db.ListAuthors(ctx)
if err != nil {
    return err
}
fmt.Println(authors)

// create an author
insertedAuthor, err := db.CreateAuthor(ctx, db.CreateAuthorParams{
        Name: "Brian Kernighan",
        Bio:  sql.NullString{String: "Co-author of The C Programming Language and The Go Programming Language", Valid: true},
})
if err != nil {
        return err
}
fmt.Println(insertedAuthor)

// get the author we just inserted
fetchedAuthor, err := db.GetAuthor(ctx, insertedAuthor.ID)
if err != nil {
        return err
}
// prints true
fmt.Println(reflect.DeepEqual(insertedAuthor, fetchedAuthor))

To make that possible, sqlc generates readable, idiomatic Go code that you otherwise would have had to write yourself. Take a look:

package db

import (
	"context"
	"database/sql"
)

type Author struct {
	ID   int64
	Name string
	Bio  sql.NullString
}

const createAuthor = `-- name: CreateAuthor :one
INSERT INTO authors (
  name, bio
) VALUES (
  $1, $2
)
RETURNING id, name, bio
`

type CreateAuthorParams struct {
	Name string
	Bio  sql.NullString
}

func (q *Queries) CreateAuthor(ctx context.Context, arg CreateAuthorParams) (Author, error) {
	row := q.db.QueryRowContext(ctx, createAuthor, arg.Name, arg.Bio)
	var i Author
	err := row.Scan(&i.ID, &i.Name, &i.Bio)
	return i, err
}

const deleteAuthor = `-- name: DeleteAuthor :exec
DELETE FROM authors
WHERE id = $1
`

func (q *Queries) DeleteAuthor(ctx context.Context, id int64) error {
	_, err := q.db.ExecContext(ctx, deleteAuthor, id)
	return err
}

const getAuthor = `-- name: GetAuthor :one
SELECT id, name, bio FROM authors
WHERE id = $1 LIMIT 1
`

func (q *Queries) GetAuthor(ctx context.Context, id int64) (Author, error) {
	row := q.db.QueryRowContext(ctx, getAuthor, id)
	var i Author
	err := row.Scan(&i.ID, &i.Name, &i.Bio)
	return i, err
}

const listAuthors = `-- name: ListAuthors :many
SELECT id, name, bio FROM authors
ORDER BY name
`

func (q *Queries) ListAuthors(ctx context.Context) ([]Author, error) {
	rows, err := q.db.QueryContext(ctx, listAuthors)
	 if err != nil {
		return nil, err
	}
	defer rows.Close()
	var items []Author
	for rows.Next() {
		var i Author
		if err := rows.Scan(&i.ID, &i.Name, &i.Bio); err != nil {
			 return nil, err
		}
		items = append(items, i)
	}
	if err := rows.Close(); err != nil {
		return nil, err
	}
	if err := rows.Err(); err != nil {
		return nil, err
	}
	return items, nil
}

type DBTX interface {
	ExecContext(context.Context, string, ...interface{}) (sql.Result, error)
	PrepareContext(context.Context, string) (*sql.Stmt, error)
	QueryContext(context.Context, string, ...interface{}) (*sql.Rows, error)
	QueryRowContext(context.Context, string, ...interface{}) *sql.Row
}

func New(db DBTX) *Queries {
	return &Queries{db: db}
}

type Queries struct {
	db DBTX
}

func (q *Queries) WithTx(tx *sql.Tx) *Queries {
	return &Queries{
		db: tx,
	}
}