Database.Groundhog.Generic

This helper module is intended for use by the backend creators

Migration

createMigration :: Monad m => Migration m -> m NamedMigrations

Produce the migrations but not execute them. Fails when an unsafe migration occurs.

executeMigration :: (PersistBackend m, MonadIO m) => NamedMigrations -> m ()

Execute the migrations with printing to stderr. Fails when an unsafe migration occurs.

executeMigrationSilent :: (PersistBackend m, MonadIO m) => NamedMigrations -> m ()

Execute the migrations. Fails when an unsafe migration occurs.

executeMigrationUnsafe :: (PersistBackend m, MonadIO m) => NamedMigrations -> m ()

Execute migrations. Executes the unsafe migrations without warnings and prints them to stderr

runMigration :: (PersistBackend m, MonadIO m) => Migration m -> m ()

Creates migrations and executes them with printing to stderr. Fails when an unsafe migration occurs. > runMigration m = createMigration m >>= executeMigration

runMigrationSilent :: (PersistBackend m, MonadIO m) => Migration m -> m ()

Creates migrations and silently executes them. Fails when an unsafe migration occurs. > runMigration m = createMigration m >>= executeMigrationSilent

runMigrationUnsafe :: (PersistBackend m, MonadIO m) => Migration m -> m ()

Creates migrations and executes them with printing to stderr. Executes the unsafe migrations without warnings > runMigrationUnsafe m = createMigration m >>= executeMigrationUnsafe

getQueries

Arguments

:: Bool

True - support unsafe queries

-> SingleMigration

-> Either [String] [String]

Returns either a list of errors in migration or a list of queries

printMigration :: MonadIO m => NamedMigrations -> m ()

Pretty print the migrations

mergeMigrations :: [SingleMigration] -> SingleMigration

Joins the migrations. The result is either all error messages or all queries

Helper functions for defining *PersistValue instances

primToPersistValue :: (PersistBackend m, PrimitivePersistField a) => a -> m ([PersistValue] -> [PersistValue])

primFromPersistValue :: (PersistBackend m, PrimitivePersistField a) => [PersistValue] -> m (a, [PersistValue])

primToPurePersistValues :: PrimitivePersistField a => a -> [PersistValue] -> [PersistValue]

primFromPurePersistValues :: PrimitivePersistField a => [PersistValue] -> (a, [PersistValue])

primToSinglePersistValue :: (PersistBackend m, PrimitivePersistField a) => a -> m PersistValue

primFromSinglePersistValue :: (PersistBackend m, PrimitivePersistField a) => PersistValue -> m a

pureToPersistValue :: (PersistBackend m, PurePersistField a) => a -> m ([PersistValue] -> [PersistValue])

pureFromPersistValue :: (PersistBackend m, PurePersistField a) => [PersistValue] -> m (a, [PersistValue])

singleToPersistValue :: (PersistBackend m, SinglePersistField a) => a -> m ([PersistValue] -> [PersistValue])

singleFromPersistValue :: (PersistBackend m, SinglePersistField a) => [PersistValue] -> m (a, [PersistValue])

toSinglePersistValueUnique :: forall m v u. (PersistBackend m, PersistEntity v, IsUniqueKey (Key v (Unique u)), PrimitivePersistField (Key v (Unique u))) => u (UniqueMarker v) -> v -> m PersistValue

fromSinglePersistValueUnique :: forall m v u. (PersistBackend m, PersistEntity v, IsUniqueKey (Key v (Unique u)), PrimitivePersistField (Key v (Unique u))) => u (UniqueMarker v) -> PersistValue -> m v

toPersistValuesUnique :: forall m v u. (PersistBackend m, PersistEntity v, IsUniqueKey (Key v (Unique u))) => u (UniqueMarker v) -> v -> m ([PersistValue] -> [PersistValue])

fromPersistValuesUnique :: forall m v u. (PersistBackend m, PersistEntity v, IsUniqueKey (Key v (Unique u))) => u (UniqueMarker v) -> [PersistValue] -> m (v, [PersistValue])

toSinglePersistValueAutoKey :: forall m v. (PersistBackend m, PersistEntity v, PrimitivePersistField (AutoKey v)) => v -> m PersistValue

fromSinglePersistValueAutoKey :: forall m v. (PersistBackend m, PersistEntity v, PrimitivePersistField (Key v BackendSpecific)) => PersistValue -> m v

failMessage :: PersistField a => a -> [PersistValue] -> String

failMessageNamed :: String -> [PersistValue] -> String

Other

bracket

Arguments

:: MonadBaseControl IO m

=> m a

computation to run first ("acquire resource")

-> (a -> m b)

computation to run last ("release resource")

-> (a -> m c)

computation to run in-between

-> m c

finally

Arguments

:: MonadBaseControl IO m

=> m a

computation to run first

-> m b

computation to run afterward (even if an exception was raised)

-> m a

onException :: MonadBaseControl IO m => m a -> m b -> m a

data PSFieldDef str

Constructors

PSFieldDef

Fields

• psFieldName :: str

  name in the record, bar

• psDbFieldName :: Maybe str

  column name, SQLbar

• psDbTypeName :: Maybe str

  column type, inet, NUMERIC(5, 2), VARCHAR(50), etc.

• psExprName :: Maybe str

  name of constructor in the Field GADT, BarField

• psEmbeddedDef :: Maybe [PSFieldDef str]
• psDefaultValue :: Maybe str

  default value in the database

• psReferenceParent :: Maybe (Maybe ((Maybe str, str), [str]), Maybe ReferenceActionType, Maybe ReferenceActionType)
• psFieldConverter :: Maybe str

  name of a pair of functions

Instances

Eq str => Eq (PSFieldDef str)

Defined in Database.Groundhog.Generic

Methods

(==) :: PSFieldDef str -> PSFieldDef str -> Bool

(/=) :: PSFieldDef str -> PSFieldDef str -> Bool

Show str => Show (PSFieldDef str)

Defined in Database.Groundhog.Generic

Methods

showsPrec :: Int -> PSFieldDef str -> ShowS

show :: PSFieldDef str -> String

showList :: [PSFieldDef str] -> ShowS

applyDbTypeSettings :: PSFieldDef String -> DbType -> DbType

findOne :: (Eq x, Show x) => String -> (a -> x) -> x -> [a] -> a

replaceOne :: (Eq x, Show x) => String -> (a -> x) -> (b -> x) -> (a -> b -> b) -> a -> [b] -> [b]

matchElements :: Show a => (a -> b -> Bool) -> [a] -> [b] -> ([a], [b], [(a, b)])

Returns only old elements, only new elements, and matched pairs (old, new). The new ones exist only in datatype, the old are present only in DB, match is typically by name (the properties of the matched elements may differ).

haveSameElems :: Show a => (a -> b -> Bool) -> [a] -> [b] -> Bool

phantomDb :: PersistBackend m => m (proxy (Conn m))

getDefaultAutoKeyType :: DbDescriptor db => proxy db -> DbTypePrimitive

getUniqueFields :: UniqueDef' str (Either field str) -> [field]

isSimple :: [ConstructorDef] -> Bool

firstRow :: MonadIO m => RowStream a -> m (Maybe a)

streamToList :: MonadIO m => RowStream a -> m [a]

mapStream :: PersistBackendConn conn => (a -> Action conn b) -> RowStream a -> Action conn (RowStream b)

joinStreams :: [Action conn (RowStream a)] -> Action conn (RowStream a)