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getting-started-sqlite.md
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getting-started-sqlite.md
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# Getting started with SQLite
This tutorial assumes that the latest version of sqlc is
[installed](../overview/install.md) and ready to use.
We'll generate Go code here, but other
[language plugins](../reference/language-support.rst) 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`
```shell
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:
```yaml
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:
```sql
CREATE TABLE authors (
id INTEGER PRIMARY KEY,
name text NOT NULL,
bio text
);
```
Next, create a `query.sql` file with the following five queries:
```sql
-- 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:
```sql
-- 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:
```shell
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:
```go
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:
```shell
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.