Safe Haskell	None
Language	Haskell2010

Database.Migrant

Synopsis

class Driver d where
- withTransaction :: (d -> IO a) -> d -> IO a
- initMigrations :: d -> IO ()
- markUp :: MigrationName -> d -> IO ()
- markDown :: MigrationName -> d -> IO ()
- getMigrations :: d -> IO [MigrationName]
data MigrationName
data MigrationDirection
migrate :: Driver d => [MigrationName] -> (MigrationName -> d -> IO ()) -> (MigrationName -> d -> IO ()) -> d -> IO ()
plan :: Driver d => [MigrationName] -> d -> IO [(MigrationDirection, MigrationName)]

Documentation

class Driver d where Source #

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

Methods

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

initMigrations :: d -> IO () Source #

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 () Source #

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

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

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

getMigrations :: d -> IO [MigrationName] Source #

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

Instances

Instances details

Driver DummyDriver Source #
Instance details Defined in Database.Migrant.Driver.Class Methods withTransaction :: (DummyDriver -> IO a) -> DummyDriver -> IO a Source # initMigrations :: DummyDriver -> IO () Source # markUp :: MigrationName -> DummyDriver -> IO () Source # markDown :: MigrationName -> DummyDriver -> IO () Source # getMigrations :: DummyDriver -> IO [MigrationName] Source #

data MigrationName Source #

Instances

Instances details

Eq MigrationName Source #
Instance details Defined in Database.Migrant.MigrationName Methods (==) :: MigrationName -> MigrationName -> Bool # (/=) :: MigrationName -> MigrationName -> Bool #
Show MigrationName Source #
Instance details Defined in Database.Migrant.MigrationName Methods showsPrec :: Int -> MigrationName -> ShowS # show :: MigrationName -> String # showList :: [MigrationName] -> ShowS #
IsString MigrationName Source #
Instance details Defined in Database.Migrant.MigrationName Methods fromString :: String -> MigrationName #
PrintfArg MigrationName Source #
Instance details Defined in Database.Migrant.MigrationName Methods formatArg :: MigrationName -> FieldFormatter # parseFormat :: MigrationName -> ModifierParser #

data MigrationDirection Source #

Instances

Instances details

Bounded MigrationDirection Source #
Instance details Defined in Database.Migrant.Run Methods minBound :: MigrationDirection # maxBound :: MigrationDirection #
Enum MigrationDirection Source #
Instance details Defined in Database.Migrant.Run Methods succ :: MigrationDirection -> MigrationDirection # pred :: MigrationDirection -> MigrationDirection # toEnum :: Int -> MigrationDirection # fromEnum :: MigrationDirection -> Int # enumFrom :: MigrationDirection -> [MigrationDirection] # enumFromThen :: MigrationDirection -> MigrationDirection -> [MigrationDirection] # enumFromTo :: MigrationDirection -> MigrationDirection -> [MigrationDirection] # enumFromThenTo :: MigrationDirection -> MigrationDirection -> MigrationDirection -> [MigrationDirection] #
Eq MigrationDirection Source #
Instance details Defined in Database.Migrant.Run Methods (==) :: MigrationDirection -> MigrationDirection -> Bool # (/=) :: MigrationDirection -> MigrationDirection -> Bool #
Ord MigrationDirection Source #
Instance details Defined in Database.Migrant.Run Methods compare :: MigrationDirection -> MigrationDirection -> Ordering # (<) :: MigrationDirection -> MigrationDirection -> Bool # (<=) :: MigrationDirection -> MigrationDirection -> Bool # (>) :: MigrationDirection -> MigrationDirection -> Bool # (>=) :: MigrationDirection -> MigrationDirection -> Bool # max :: MigrationDirection -> MigrationDirection -> MigrationDirection # min :: MigrationDirection -> MigrationDirection -> MigrationDirection #
Show MigrationDirection Source #
Instance details Defined in Database.Migrant.Run Methods showsPrec :: Int -> MigrationDirection -> ShowS # show :: MigrationDirection -> String # showList :: [MigrationDirection] -> ShowS #

migrate Source #

Arguments

:: Driver d
=> [MigrationName]	Target situation
-> (MigrationName -> d -> IO ())	Factory for 'up' migration actions
-> (MigrationName -> d -> IO ())	Factory for 'down' migration actions
-> d
-> IO ()

Safely (transactionally) infer and execute a migration.

plan :: Driver d => [MigrationName] -> d -> IO [(MigrationDirection, MigrationName)] Source #

Create a migration plan based on the current situation on the database, and the specified target.