# migrate

`migrate` is a package for SQL database migrations in the spirit of [dbstore](rsc.io/dbstore). It is intended to keep its footprint small, requiring only an additional table in the database. There is no rollback support as you should only ever roll forward. SQLite and PostgreSQL support is provided, support for other databases can be added by implementing the `Dialect` interface.

## Installation

```bash
go get git.sdf.org/jchenry/migrate
```

## Usage

### SQLite Example

```go
import (
	"database/sql"
	"git.sdf.org/jchenry/migrate"
	_ "modernc.org/sqlite"
)

db, _ := sql.Open("sqlite", "database.db")

changes := []migrate.Change{
	{
		Description: "create people table",
		Apply: func(ctx migrate.Context) error {
			_, err := ctx.Exec(`
				CREATE TABLE people (
					given_name VARCHAR(20),
					surname VARCHAR(30),
					sex CHAR(1),
					age SMALLINT);
			`)
			return err
		},
	},
	{
		Description: "Insert a person into people",
		Apply: func(ctx migrate.Context) error {
			_, err := ctx.Exec(`INSERT INTO people VALUES('Henry','Colin','M', 42)`)
			return err
		},
	},
}

err := migrate.Apply(db, migrate.Sqlite3(), changes)
if err != nil {
	// handle error
}
```

### PostgreSQL Example

```go
import (
	"database/sql"
	"git.sdf.org/jchenry/migrate"
	_ "github.com/lib/pq"
)

db, _ := sql.Open("postgres", "postgres://user:password@localhost/dbname?sslmode=disable")

changes := []migrate.Change{
	{
		Description: "create people table",
		Apply: func(ctx migrate.Context) error {
			_, err := ctx.Exec(`
				CREATE TABLE people (
					given_name VARCHAR(20),
					surname VARCHAR(30),
					sex CHAR(1),
					age SMALLINT);
			`)
			return err
		},
	},
}

err := migrate.Apply(db, migrate.Postgres(), changes)
if err != nil {
	// handle error
}
```

## Supported Databases

- **SQLite** - Use `migrate.Sqlite3()`
- **PostgreSQL** - Use `migrate.Postgres()`

To add support for other databases, implement the `Dialect` interface.

## Contributing
Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

## License
[MIT](https://choosealicense.com/licenses/mit/)