dbm

A simple database migration tool.

Philosophy

The idea here is to create the simplest, stupidest, dumbest thing that could possibly work.

dbm is made to sit outside of other projects - it's not tied to any framework and although it's written in Haskell it can certainly be used with projects in other environments.

To use it, simply create a sql/ directory in your project's root directory, with your migrations. Name the migrations ###-some-short-description.sql. e.g. 001.initial-schema.sql.

Then create a file, sql/.dbm, that describes how to access your database in certain environments.

For example

[development]
backend = sqlite
path = /tmp/inventory.sql

That's it! Now you can run dbm initialize <your environment> which will add a simple table to your database to keep track of migration data. See dbm -h for a full list of commands, but briefly:

• dbm initialize <env> will create the dbm_migrations table in your database for keeping track of migration status.
• dbm status <env> will show you which migrations need to be applied, if any.
• dbm migrate <env> will migrate your database to the latest migration.

What works, what doesn't?

• There is no notation of "undoing" a migration. This is by design to keep things simple, although if it is something you need, open an issue. :)
• Right now, only SQLite is supported, but it should be easy to add other backends. We use the $database-simple Hackage packages, so in theory adding at least MySQL and PostgreSQL should be near-trivial.

License

BSD-3, see LICENSE.