Getting started with SQLite
This tutorial assumes that the latest version of sqlc is installed and ready to use.
We’ll generate Go code here, but other language plugins are available. You’ll naturally need the Go toolchain if you want to build and run a program with the code sqlc generates, but sqlc itself has no dependencies.
Setting up
Create a new directory called sqlc-tutorial
and open it up.
Initialize a new Go module named tutorial.sqlc.dev/app
go mod init tutorial.sqlc.dev/app
sqlc looks for either a sqlc.(yaml|yml)
or sqlc.json
file in the current
directory. In our new directory, create a file named sqlc.yaml
with the
following contents:
version: "2"
sql:
- engine: "sqlite"
queries: "query.sql"
schema: "schema.sql"
gen:
go:
package: "tutorial"
out: "tutorial"
Schema and queries
sqlc needs to know your database schema and queries in order to generate code.
In the same directory, create a file named schema.sql
with the following
content:
CREATE TABLE authors (
id INTEGER PRIMARY KEY,
name text NOT NULL,
bio text
);
Next, create a query.sql
file with the following five queries:
-- name: GetAuthor :one
SELECT * FROM authors
WHERE id = ? LIMIT 1;
-- name: ListAuthors :many
SELECT * FROM authors
ORDER BY name;
-- name: CreateAuthor :one
INSERT INTO authors (
name, bio
) VALUES (
?, ?
)
RETURNING *;
-- name: UpdateAuthor :exec
UPDATE authors
set name = ?,
bio = ?
WHERE id = ?;
-- name: DeleteAuthor :exec
DELETE FROM authors
WHERE id = ?;
If you prefer, you can alter the UpdateAuthor
query to return the updated
record:
-- name: UpdateAuthor :one
UPDATE authors
set name = ?,
bio = ?
WHERE id = ?
RETURNING *;
Generating code
You are now ready to generate code. You shouldn’t see any output when you run
the generate
subcommand, unless something goes wrong:
sqlc generate
You should now have a tutorial
subdirectory with three files containing Go
source code. These files comprise a Go package named tutorial
:
├── go.mod
├── query.sql
├── schema.sql
├── sqlc.yaml
└── tutorial
├── db.go
├── models.go
└── query.sql.go
Using generated code
You can use your newly-generated tutorial
package from any Go program.
Create a file named tutorial.go
and add the following contents:
package main
import (
"context"
"database/sql"
_ "embed"
"log"
"reflect"
_ "github.com/mattn/go-sqlite3"
"tutorial.sqlc.dev/app/tutorial"
)
//go:embed schema.sql
var ddl string
func run() error {
ctx := context.Background()
db, err := sql.Open("sqlite3", ":memory:")
if err != nil {
return err
}
// create tables
if _, err := db.ExecContext(ctx, ddl); err != nil {
return err
}
queries := tutorial.New(db)
// list all authors
authors, err := queries.ListAuthors(ctx)
if err != nil {
return err
}
log.Println(authors)
// create an author
insertedAuthor, err := queries.CreateAuthor(ctx, tutorial.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
}
log.Println(insertedAuthor)
// get the author we just inserted
fetchedAuthor, err := queries.GetAuthor(ctx, insertedAuthor.ID)
if err != nil {
return err
}
// prints true
log.Println(reflect.DeepEqual(insertedAuthor, fetchedAuthor))
return nil
}
func main() {
if err := run(); err != nil {
log.Fatal(err)
}
}
Before this code will compile you’ll need to fetch the relevant SQLite driver:
go get github.com/mattn/go-sqlite3
go build ./...
The program should compile without errors, and run successfully. To make that
possible, sqlc generates readable, idiomatic Go code that you
otherwise would’ve had to write yourself. Take a look in tutorial/query.sql.go
.
You should now have a working program using sqlc’s generated Go source code, and hopefully can see how you’d use sqlc in your own real-world applications.