Database.PostgreSQL.Simple.Migration

A migration library for postgresql-simple.

For usage, see Readme.markdown.

Migration actions

runMigration :: MigrationContext -> IO (MigrationResult String)

Executes migrations inside the provided MigrationContext.

Returns MigrationSuccess if the provided MigrationCommand executes without error. If an error occurs, execution is stopped and a MigrationError is returned.

It is recommended to wrap runMigration inside a database transaction.

runMigrations

Arguments

:: Bool

Run in verbose mode

-> Connection

The postgres connection to use

-> [MigrationCommand]

The commands to run

-> IO (MigrationResult String)

Execute a sequence of migrations

Returns MigrationSuccess if all of the provided MigrationCommands execute without error. If an error occurs, execution is stopped and the MigrationError is returned.

It is recommended to wrap runMigrations inside a database transaction.

sequenceMigrations :: Monad m => [m (MigrationResult e)] -> m (MigrationResult e)

Run a sequence of contexts, stopping on the first failure

Migration types

data MigrationContext

The MigrationContext provides an execution context for migrations.

Constructors

MigrationContext

Fields

• migrationContextCommand :: MigrationCommand

  The action that will be performed by runMigration

• migrationContextVerbose :: Bool

  Verbosity of the library.

• migrationContextConnection :: Connection

  The PostgreSQL connection to use for migrations.

data MigrationCommand

MigrationCommand determines the action of the runMigration script.

Constructors

MigrationInitialization

Initializes the database with a helper table containing meta information.

MigrationDirectory FilePath

Executes migrations based on SQL scripts in the provided FilePath in alphabetical order.

MigrationFile ScriptName FilePath

Executes a migration based on script located at the provided FilePath.

MigrationScript ScriptName ByteString

Executes a migration based on the provided bytestring.

MigrationValidation MigrationCommand

Validates that the provided MigrationCommand has been executed.

MigrationCommands [MigrationCommand]

Performs a series of MigrationCommands in sequence.

Instances

Eq MigrationCommand

Methods

(==) :: MigrationCommand -> MigrationCommand -> Bool

(/=) :: MigrationCommand -> MigrationCommand -> Bool

Ord MigrationCommand

Methods

compare :: MigrationCommand -> MigrationCommand -> Ordering

(<) :: MigrationCommand -> MigrationCommand -> Bool

(<=) :: MigrationCommand -> MigrationCommand -> Bool

(>) :: MigrationCommand -> MigrationCommand -> Bool

(>=) :: MigrationCommand -> MigrationCommand -> Bool

max :: MigrationCommand -> MigrationCommand -> MigrationCommand

min :: MigrationCommand -> MigrationCommand -> MigrationCommand

Read MigrationCommand

Methods

readsPrec :: Int -> ReadS MigrationCommand

readList :: ReadS [MigrationCommand]

readPrec :: ReadPrec MigrationCommand

readListPrec :: ReadPrec [MigrationCommand]

Show MigrationCommand

Methods

showsPrec :: Int -> MigrationCommand -> ShowS

show :: MigrationCommand -> String

showList :: [MigrationCommand] -> ShowS

Monoid MigrationCommand

Methods

mempty :: MigrationCommand

mappend :: MigrationCommand -> MigrationCommand -> MigrationCommand

mconcat :: [MigrationCommand] -> MigrationCommand

data MigrationResult a

A sum-type denoting the result of a migration.

Constructors

MigrationError a

There was an error in script migration.

MigrationSuccess

All scripts have been executed successfully.

Instances

Functor MigrationResult

Methods

fmap :: (a -> b) -> MigrationResult a -> MigrationResult b

(<$) :: a -> MigrationResult b -> MigrationResult a

Foldable MigrationResult

Methods

fold :: Monoid m => MigrationResult m -> m

foldMap :: Monoid m => (a -> m) -> MigrationResult a -> m

foldr :: (a -> b -> b) -> b -> MigrationResult a -> b

foldr' :: (a -> b -> b) -> b -> MigrationResult a -> b

foldl :: (b -> a -> b) -> b -> MigrationResult a -> b

foldl' :: (b -> a -> b) -> b -> MigrationResult a -> b

foldr1 :: (a -> a -> a) -> MigrationResult a -> a

foldl1 :: (a -> a -> a) -> MigrationResult a -> a

toList :: MigrationResult a -> [a]

null :: MigrationResult a -> Bool

length :: MigrationResult a -> Int

elem :: Eq a => a -> MigrationResult a -> Bool

maximum :: Ord a => MigrationResult a -> a

minimum :: Ord a => MigrationResult a -> a

sum :: Num a => MigrationResult a -> a

product :: Num a => MigrationResult a -> a

Traversable MigrationResult

Methods

traverse :: Applicative f => (a -> f b) -> MigrationResult a -> f (MigrationResult b)

sequenceA :: Applicative f => MigrationResult (f a) -> f (MigrationResult a)

mapM :: Monad m => (a -> m b) -> MigrationResult a -> m (MigrationResult b)

sequence :: Monad m => MigrationResult (m a) -> m (MigrationResult a)

Eq a => Eq (MigrationResult a)

Methods

(==) :: MigrationResult a -> MigrationResult a -> Bool

(/=) :: MigrationResult a -> MigrationResult a -> Bool

Ord a => Ord (MigrationResult a)

Methods

compare :: MigrationResult a -> MigrationResult a -> Ordering

(<) :: MigrationResult a -> MigrationResult a -> Bool

(<=) :: MigrationResult a -> MigrationResult a -> Bool

(>) :: MigrationResult a -> MigrationResult a -> Bool

(>=) :: MigrationResult a -> MigrationResult a -> Bool

max :: MigrationResult a -> MigrationResult a -> MigrationResult a

min :: MigrationResult a -> MigrationResult a -> MigrationResult a

Read a => Read (MigrationResult a)

Methods

readsPrec :: Int -> ReadS (MigrationResult a)

readList :: ReadS [MigrationResult a]

readPrec :: ReadPrec (MigrationResult a)

readListPrec :: ReadPrec [MigrationResult a]

Show a => Show (MigrationResult a)

Methods

showsPrec :: Int -> MigrationResult a -> ShowS

show :: MigrationResult a -> String

showList :: [MigrationResult a] -> ShowS

type ScriptName = String

The name of a script. Typically the filename or a custom name when using Haskell migrations.

type Checksum = ByteString

The checksum type of a migration script.

Migration result actions

getMigrations :: Connection -> IO [SchemaMigration]

Produces a list of all executed SchemaMigrations.

Migration result types

data SchemaMigration

A product type representing a single, executed SchemaMigration.

Constructors

SchemaMigration

Fields

• schemaMigrationName :: ByteString

  The name of the executed migration.

• schemaMigrationChecksum :: Checksum

  The calculated MD5 checksum of the executed script.

• schemaMigrationExecutedAt :: LocalTime

  A timestamp without timezone of the date of execution of the script.

Instances

Eq SchemaMigration

Methods

(==) :: SchemaMigration -> SchemaMigration -> Bool

(/=) :: SchemaMigration -> SchemaMigration -> Bool

Ord SchemaMigration

Methods

compare :: SchemaMigration -> SchemaMigration -> Ordering

(<) :: SchemaMigration -> SchemaMigration -> Bool

(<=) :: SchemaMigration -> SchemaMigration -> Bool

(>) :: SchemaMigration -> SchemaMigration -> Bool

(>=) :: SchemaMigration -> SchemaMigration -> Bool

max :: SchemaMigration -> SchemaMigration -> SchemaMigration

min :: SchemaMigration -> SchemaMigration -> SchemaMigration

Read SchemaMigration

Methods

readsPrec :: Int -> ReadS SchemaMigration

readList :: ReadS [SchemaMigration]

readPrec :: ReadPrec SchemaMigration

readListPrec :: ReadPrec [SchemaMigration]

Show SchemaMigration

Methods

showsPrec :: Int -> SchemaMigration -> ShowS

show :: SchemaMigration -> String

showList :: [SchemaMigration] -> ShowS

ToRow SchemaMigration

Methods

toRow :: SchemaMigration -> [Action]

FromRow SchemaMigration

Methods

fromRow :: RowParser SchemaMigration