# pgmigrate

Migration tool for postgres databases in node.js.
`pgmigrate` helps you to migrate your schema for postgres.

- use it from cli or via javascript
- zero dependencies
- tested code

## usage

It is possible to use pgmigrate via cli tools are programmatically.
`node_modules/.bin` contains `add-migration` and `migrate`.

### add-migration

`add-migration <name>` will add a migration file to `schema/$timestamp-$name.sql`.
Custom SQl can be written into this file.

### migrate via the cli

`migrate` will execute all sql files in schema which are not yet executed.

Usage:

```bash
DATABASE_URL=postgres://user:pass@server/database node_modules/.bin/migrate
```

Adding `--sync` will truncate the database before running migrate.

```bash
DATABASE_URL=postgres://user:pass@server/database node_modules/.bin/migrate --sync
```

### migrate via code

```javascript
const pg = require('pg');
const migrate = require('pgmigrate');
const getConnection = cb => pg.connect(process.env.DATABASE_URL, cb);
migrate('path/to/schema', getConnection, {isSync: false})
  .then(console.log)
  .catch(console.error);
```

## technical implementation

`pgmigrate` adds a schema table to your database called `schema_info`.
In `schema_info` all filenames of all already executed schema migrations are persisted.
As soon as a schema is executed successful, the filename is added to this table.

All sql files in `path_to_migrations` which are not yet in the database are executed.
After successful execution the timestamp of the migration file is added to the `schema_info` table.

The format of the migrations files should be `$iso8601-description.sql`

```
YYYY-MM-DDTHH:MM:SSZ-description.sql
```

## Hooks

Sometimes you want to execute sql logic always before and/or after you run your migrations.
In this case you can add pre and post hooks to your schema folder.

For a prehook use a filename with this pattern: `0000-00-00T00:00:00:000Z-$description.sql`
For a posthook use a filename with this pattern: `9999-99-99T99:99:99:999Z-$description.sql`

License MIT