Database.Migrant.Driver.Class

Documentation

class Driver d where

A migrations driver abstracts over the database to run over and the associated migration mechanism.

Methods

withTransaction :: (d -> IO a) -> d -> IO a

initMigrations :: d -> IO ()

Initialize the migrations system on the backend. This should generally involve creating a table of ordered migration names, e.g.: @@ CREATE TABLE IF NOT EXISTS _migrations (id SERIAL PRIMARY KEY, name TEXT); @@

• *Note** that initMigrations should be idempotent, that is, executing it when the migrations system has already been initialized should be a no-op.

markUp :: MigrationName -> d -> IO ()

Mark a migration as "executed". Typically, this will INSERT a row into the migrations table.

markDown :: MigrationName -> d -> IO ()

Mark a migration as "not executed" / "rolled back". Typically, this will DELETE a row from the migrations table.

getMigrations :: d -> IO [MigrationName]

Get the list of migrations applied to the backend, in the order they were applied.

Instances

Driver DummyDriver

Defined in Database.Migrant.Driver.Class

Methods

withTransaction :: (DummyDriver -> IO a) -> DummyDriver -> IO a

initMigrations :: DummyDriver -> IO ()

markUp :: MigrationName -> DummyDriver -> IO ()

markDown :: MigrationName -> DummyDriver -> IO ()

getMigrations :: DummyDriver -> IO [MigrationName]

data DummyDriver

Constructors

DummyDriver

Instances

Driver DummyDriver

Defined in Database.Migrant.Driver.Class

Methods

withTransaction :: (DummyDriver -> IO a) -> DummyDriver -> IO a

initMigrations :: DummyDriver -> IO ()

markUp :: MigrationName -> DummyDriver -> IO ()

markDown :: MigrationName -> DummyDriver -> IO ()

getMigrations :: DummyDriver -> IO [MigrationName]