Safe Haskell | Safe-Inferred |
---|---|
Language | Haskell2010 |
Classy shim around Database.Esqueleto.Legacy
In the style of Database.Persist.Monad
, this exposes a "classy"
(typeclass-using) API for Esqueleto functions, allowing them to be
used with MonadSqlQuery
constraints rather than a
concrete type.ReaderT
SqlBackend
The goal of this module is to be a drop-in replacement for
Database.Esqueleto.Legacy
.
Synopsis
- select :: (MonadSqlQuery m, SqlSelect a r) => SqlQuery a -> m [r]
- selectOne :: (MonadSqlQuery m, SqlSelect a r) => SqlQuery a -> m (Maybe r)
- delete :: MonadSqlQuery m => SqlQuery () -> m ()
- update :: (MonadSqlQuery m, PersistEntity val, BackendCompatible SqlBackend (PersistEntityBackend val)) => (SqlExpr (Entity val) -> SqlQuery ()) -> m ()
- renderQuerySelect :: (MonadSqlQuery m, SqlSelect a r) => SqlQuery a -> m (Text, [PersistValue])
- deleteWhere :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => [Filter record] -> m ()
- get :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => Key record -> m (Maybe record)
- getBy :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => Unique record -> m (Maybe (Entity record))
- getEntity :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => Key record -> m (Maybe (Entity record))
- getMany :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => [Key record] -> m (Map (Key record) record)
- insert :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => record -> m (Key record)
- insert_ :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => record -> m ()
- insertKey :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => Key record -> record -> m ()
- insertMany_ :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => [record] -> m ()
- insertEntityMany :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => [Entity record] -> m ()
- selectFirst :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => [Filter record] -> [SelectOpt record] -> m (Maybe (Entity record))
- updateWhere :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => [Filter record] -> [Update record] -> m ()
- associateJoin :: forall e1 e0. Ord (Key e0) => [(Entity e0, e1)] -> Map (Key e0) (e0, [e1])
- deleteKey :: forall backend val (m :: Type -> Type). (PersistStore backend, BaseBackend backend ~ PersistEntityBackend val, MonadIO m, PersistEntity val) => Key val -> ReaderT backend m ()
- valJ :: PersistField (Key entity) => Value (Key entity) -> SqlExpr (Value (Key entity))
- valkey :: (ToBackendKey SqlBackend entity, PersistField (Key entity)) => Int64 -> SqlExpr (Value (Key entity))
- insertSelectCount :: forall (m :: Type -> Type) a backend. (MonadIO m, PersistEntity a, SqlBackendCanWrite backend) => SqlQuery (SqlExpr (Insertion a)) -> ReaderT backend m Int64
- insertSelect :: forall (m :: Type -> Type) a backend. (MonadIO m, PersistEntity a, SqlBackendCanWrite backend) => SqlQuery (SqlExpr (Insertion a)) -> ReaderT backend m ()
- renderQueryInsertInto :: forall a r backend (m :: Type -> Type). (SqlSelect a r, BackendCompatible SqlBackend backend, Monad m) => SqlQuery a -> ReaderT backend m (Text, [PersistValue])
- renderQueryUpdate :: forall a r backend (m :: Type -> Type). (SqlSelect a r, BackendCompatible SqlBackend backend, Monad m) => SqlQuery a -> ReaderT backend m (Text, [PersistValue])
- renderQueryDelete :: forall a r backend (m :: Type -> Type). (SqlSelect a r, BackendCompatible SqlBackend backend, Monad m) => SqlQuery a -> ReaderT backend m (Text, [PersistValue])
- renderQueryToText :: forall a r backend (m :: Type -> Type). (SqlSelect a r, BackendCompatible SqlBackend backend, Monad m) => Mode -> SqlQuery a -> ReaderT backend m (Text, [PersistValue])
- updateCount :: forall (m :: Type -> Type) val backend. (MonadIO m, PersistEntity val, BackendCompatible SqlBackend (PersistEntityBackend val), SqlBackendCanWrite backend) => (SqlExpr (Entity val) -> SqlQuery ()) -> ReaderT backend m Int64
- deleteCount :: forall (m :: Type -> Type) backend. (MonadIO m, SqlBackendCanWrite backend) => SqlQuery () -> ReaderT backend m Int64
- selectSource :: forall a r backend (m :: Type -> Type). (SqlSelect a r, BackendCompatible SqlBackend backend, IsPersistBackend backend, PersistQueryRead backend, PersistStoreRead backend, PersistUniqueRead backend, MonadResource m) => SqlQuery a -> ConduitT () r (ReaderT backend m) ()
- from :: From a => (a -> SqlQuery b) -> SqlQuery b
- else_ :: expr a -> expr a
- then_ :: ()
- when_ :: expr (Value Bool) -> () -> expr a -> (expr (Value Bool), expr a)
- toBaseId :: ToBaseId ent => SqlExpr (Value (Key ent)) -> SqlExpr (Value (Key (BaseEnt ent)))
- case_ :: PersistField a => [(SqlExpr (Value Bool), SqlExpr (Value a))] -> SqlExpr (Value a) -> SqlExpr (Value a)
- (<&>) :: SqlExpr (Insertion (a -> b)) -> SqlExpr (Value a) -> SqlExpr (Insertion b)
- (<#) :: (a -> b) -> SqlExpr (Value a) -> SqlExpr (Insertion b)
- (/=.) :: (PersistEntity val, PersistField a) => EntityField val a -> SqlExpr (Value a) -> SqlExpr (Entity val) -> SqlExpr Update
- (*=.) :: (PersistEntity val, PersistField a) => EntityField val a -> SqlExpr (Value a) -> SqlExpr (Entity val) -> SqlExpr Update
- (-=.) :: (PersistEntity val, PersistField a) => EntityField val a -> SqlExpr (Value a) -> SqlExpr (Entity val) -> SqlExpr Update
- (+=.) :: (PersistEntity val, PersistField a) => EntityField val a -> SqlExpr (Value a) -> SqlExpr (Entity val) -> SqlExpr Update
- (=.) :: (PersistEntity val, PersistField typ) => EntityField val typ -> SqlExpr (Value typ) -> SqlExpr (Entity val) -> SqlExpr Update
- set :: PersistEntity val => SqlExpr (Entity val) -> [SqlExpr (Entity val) -> SqlExpr Update] -> SqlQuery ()
- notExists :: SqlQuery () -> SqlExpr (Value Bool)
- exists :: SqlQuery () -> SqlExpr (Value Bool)
- notIn :: PersistField typ => SqlExpr (Value typ) -> SqlExpr (ValueList typ) -> SqlExpr (Value Bool)
- in_ :: PersistField typ => SqlExpr (Value typ) -> SqlExpr (ValueList typ) -> SqlExpr (Value Bool)
- justList :: SqlExpr (ValueList typ) -> SqlExpr (ValueList (Maybe typ))
- valList :: PersistField typ => [typ] -> SqlExpr (ValueList typ)
- subList_select :: PersistField a => SqlQuery (SqlExpr (Value a)) -> SqlExpr (ValueList a)
- castString :: (SqlString s, SqlString r) => SqlExpr (Value s) -> SqlExpr (Value r)
- (++.) :: SqlString s => SqlExpr (Value s) -> SqlExpr (Value s) -> SqlExpr (Value s)
- concat_ :: SqlString s => [SqlExpr (Value s)] -> SqlExpr (Value s)
- (%) :: SqlString s => SqlExpr (Value s)
- ilike :: SqlString s => SqlExpr (Value s) -> SqlExpr (Value s) -> SqlExpr (Value Bool)
- like :: SqlString s => SqlExpr (Value s) -> SqlExpr (Value s) -> SqlExpr (Value Bool)
- right_ :: (SqlString s, Num a) => (SqlExpr (Value s), SqlExpr (Value a)) -> SqlExpr (Value s)
- left_ :: (SqlString s, Num a) => (SqlExpr (Value s), SqlExpr (Value a)) -> SqlExpr (Value s)
- length_ :: (SqlString s, Num a) => SqlExpr (Value s) -> SqlExpr (Value a)
- ltrim_ :: SqlString s => SqlExpr (Value s) -> SqlExpr (Value s)
- rtrim_ :: SqlString s => SqlExpr (Value s) -> SqlExpr (Value s)
- trim_ :: SqlString s => SqlExpr (Value s) -> SqlExpr (Value s)
- upper_ :: SqlString s => SqlExpr (Value s) -> SqlExpr (Value s)
- lower_ :: SqlString s => SqlExpr (Value s) -> SqlExpr (Value s)
- coalesceDefault :: PersistField a => [SqlExpr (Value (Maybe a))] -> SqlExpr (Value a) -> SqlExpr (Value a)
- coalesce :: PersistField a => [SqlExpr (Value (Maybe a))] -> SqlExpr (Value (Maybe a))
- castNumM :: (Num a, Num b) => SqlExpr (Value (Maybe a)) -> SqlExpr (Value (Maybe b))
- castNum :: (Num a, Num b) => SqlExpr (Value a) -> SqlExpr (Value b)
- avg_ :: (PersistField a, PersistField b) => SqlExpr (Value a) -> SqlExpr (Value (Maybe b))
- max_ :: PersistField a => SqlExpr (Value a) -> SqlExpr (Value (Maybe a))
- min_ :: PersistField a => SqlExpr (Value a) -> SqlExpr (Value (Maybe a))
- sum_ :: (PersistField a, PersistField b) => SqlExpr (Value a) -> SqlExpr (Value (Maybe b))
- floor_ :: (PersistField a, Num a, PersistField b, Num b) => SqlExpr (Value a) -> SqlExpr (Value b)
- ceiling_ :: (PersistField a, Num a, PersistField b, Num b) => SqlExpr (Value a) -> SqlExpr (Value b)
- round_ :: (PersistField a, Num a, PersistField b, Num b) => SqlExpr (Value a) -> SqlExpr (Value b)
- random_ :: (PersistField a, Num a) => SqlExpr (Value a)
- between :: PersistField a => SqlExpr (Value a) -> (SqlExpr (Value a), SqlExpr (Value a)) -> SqlExpr (Value Bool)
- (*.) :: PersistField a => SqlExpr (Value a) -> SqlExpr (Value a) -> SqlExpr (Value a)
- (/.) :: PersistField a => SqlExpr (Value a) -> SqlExpr (Value a) -> SqlExpr (Value a)
- (-.) :: PersistField a => SqlExpr (Value a) -> SqlExpr (Value a) -> SqlExpr (Value a)
- (+.) :: PersistField a => SqlExpr (Value a) -> SqlExpr (Value a) -> SqlExpr (Value a)
- (||.) :: SqlExpr (Value Bool) -> SqlExpr (Value Bool) -> SqlExpr (Value Bool)
- (&&.) :: SqlExpr (Value Bool) -> SqlExpr (Value Bool) -> SqlExpr (Value Bool)
- (!=.) :: PersistField typ => SqlExpr (Value typ) -> SqlExpr (Value typ) -> SqlExpr (Value Bool)
- (<.) :: PersistField typ => SqlExpr (Value typ) -> SqlExpr (Value typ) -> SqlExpr (Value Bool)
- (<=.) :: PersistField typ => SqlExpr (Value typ) -> SqlExpr (Value typ) -> SqlExpr (Value Bool)
- (>.) :: PersistField typ => SqlExpr (Value typ) -> SqlExpr (Value typ) -> SqlExpr (Value Bool)
- (>=.) :: PersistField typ => SqlExpr (Value typ) -> SqlExpr (Value typ) -> SqlExpr (Value Bool)
- (==.) :: PersistField typ => SqlExpr (Value typ) -> SqlExpr (Value typ) -> SqlExpr (Value Bool)
- not_ :: SqlExpr (Value Bool) -> SqlExpr (Value Bool)
- countDistinct :: Num a => SqlExpr (Value typ) -> SqlExpr (Value a)
- count :: Num a => SqlExpr (Value typ) -> SqlExpr (Value a)
- countRows :: Num a => SqlExpr (Value a)
- joinV :: SqlExpr (Value (Maybe (Maybe typ))) -> SqlExpr (Value (Maybe typ))
- nothing :: SqlExpr (Value (Maybe typ))
- just :: SqlExpr (Value typ) -> SqlExpr (Value (Maybe typ))
- isNothing :: PersistField typ => SqlExpr (Value (Maybe typ)) -> SqlExpr (Value Bool)
- val :: PersistField typ => typ -> SqlExpr (Value typ)
- (?.) :: (PersistEntity val, PersistField typ) => SqlExpr (Maybe (Entity val)) -> EntityField val typ -> SqlExpr (Value (Maybe typ))
- withNonNull :: PersistField typ => SqlExpr (Value (Maybe typ)) -> (SqlExpr (Value typ) -> SqlQuery a) -> SqlQuery a
- (^.) :: forall typ val. (PersistEntity val, PersistField typ) => SqlExpr (Entity val) -> EntityField val typ -> SqlExpr (Value typ)
- subSelectUnsafe :: PersistField a => SqlQuery (SqlExpr (Value a)) -> SqlExpr (Value a)
- subSelectForeign :: (BackendCompatible SqlBackend (PersistEntityBackend val1), PersistEntity val1, PersistEntity val2, PersistField a) => SqlExpr (Entity val2) -> EntityField val2 (Key val1) -> (SqlExpr (Entity val1) -> SqlExpr (Value a)) -> SqlExpr (Value a)
- subSelectList :: PersistField a => SqlQuery (SqlExpr (Value a)) -> SqlExpr (ValueList a)
- subSelectCount :: (Num a, PersistField a) => SqlQuery ignored -> SqlExpr (Value a)
- subSelectMaybe :: PersistField a => SqlQuery (SqlExpr (Value (Maybe a))) -> SqlExpr (Value (Maybe a))
- subSelect :: PersistField a => SqlQuery (SqlExpr (Value a)) -> SqlExpr (Value (Maybe a))
- sub_select :: PersistField a => SqlQuery (SqlExpr (Value a)) -> SqlExpr (Value a)
- locking :: LockingKind -> SqlQuery ()
- having :: SqlExpr (Value Bool) -> SqlQuery ()
- rand :: SqlExpr OrderBy
- distinctOnOrderBy :: [SqlExpr OrderBy] -> SqlQuery a -> SqlQuery a
- don :: SqlExpr (Value a) -> SqlExpr DistinctOn
- distinctOn :: [SqlExpr DistinctOn] -> SqlQuery a -> SqlQuery a
- distinct :: SqlQuery a -> SqlQuery a
- offset :: Int64 -> SqlQuery ()
- limit :: Int64 -> SqlQuery ()
- desc :: PersistField a => SqlExpr (Value a) -> SqlExpr OrderBy
- asc :: PersistField a => SqlExpr (Value a) -> SqlExpr OrderBy
- orderBy :: [SqlExpr OrderBy] -> SqlQuery ()
- groupBy :: ToSomeValues a => a -> SqlQuery ()
- on :: SqlExpr (Value Bool) -> SqlQuery ()
- where_ :: SqlExpr (Value Bool) -> SqlQuery ()
- newtype Value a = Value {
- unValue :: a
- newtype ValueList a = ValueList a
- data InnerJoin a b = a `InnerJoin` b
- data CrossJoin a b = a `CrossJoin` b
- data LeftOuterJoin a b = a `LeftOuterJoin` b
- data RightOuterJoin a b = a `RightOuterJoin` b
- data FullOuterJoin a b = a `FullOuterJoin` b
- data JoinKind
- data OnClauseWithoutMatchingJoinException = OnClauseWithoutMatchingJoinException String
- data OrderBy
- data DistinctOn
- data LockingKind
- class PersistField a => SqlString a
- type family BaseEnt ent
- class ToBaseId ent where
- type BaseEnt ent
- toBaseIdWitness :: Key (BaseEnt ent) -> Key ent
- class From a
- data SqlQuery a
- type SqlEntity ent = (PersistEntity ent, PersistEntityBackend ent ~ SqlBackend)
- data SqlExpr a
- class PersistConfig c where
- type PersistConfigBackend c :: (Type -> Type) -> Type -> Type
- type PersistConfigPool c
- loadConfig :: Value -> Parser c
- applyEnv :: c -> IO c
- createPoolConfig :: c -> IO (PersistConfigPool c)
- runPool :: MonadUnliftIO m => c -> PersistConfigBackend c m a -> PersistConfigPool c -> m a
- type family PersistConfigBackend c :: (Type -> Type) -> Type -> Type
- type family PersistConfigPool c
- newtype ConstraintNameHS = ConstraintNameHS {}
- newtype ConstraintNameDB = ConstraintNameDB {}
- newtype EntityNameDB = EntityNameDB {}
- newtype EntityNameHS = EntityNameHS {}
- newtype FieldNameHS = FieldNameHS {}
- newtype FieldNameDB = FieldNameDB {}
- class DatabaseName a where
- escapeWith :: (Text -> str) -> a -> str
- data LiteralType
- data PersistValue where
- PersistText Text
- PersistByteString ByteString
- PersistInt64 Int64
- PersistDouble Double
- PersistRational Rational
- PersistBool Bool
- PersistDay Day
- PersistTimeOfDay TimeOfDay
- PersistUTCTime UTCTime
- PersistNull
- PersistList [PersistValue]
- PersistMap [(Text, PersistValue)]
- PersistObjectId ByteString
- PersistArray [PersistValue]
- PersistLiteral_ LiteralType ByteString
- pattern PersistLiteral :: ByteString -> PersistValue
- pattern PersistDbSpecific :: ByteString -> PersistValue
- pattern PersistLiteralEscaped :: ByteString -> PersistValue
- fromPersistValueText :: PersistValue -> Either Text Text
- data IsolationLevel
- data FieldDef = FieldDef {
- fieldHaskell :: !FieldNameHS
- fieldDB :: !FieldNameDB
- fieldType :: !FieldType
- fieldSqlType :: !SqlType
- fieldAttrs :: ![FieldAttr]
- fieldStrict :: !Bool
- fieldReference :: !ReferenceDef
- fieldCascade :: !FieldCascade
- fieldComments :: !(Maybe Text)
- fieldGenerated :: !(Maybe Text)
- fieldIsImplicitIdColumn :: !Bool
- data PersistUpdate
- data UpdateException
- data PersistFilter
- data SqlType
- data PersistException
- data CascadeAction
- = Cascade
- | Restrict
- | SetNull
- | SetDefault
- data FieldCascade = FieldCascade {
- fcOnUpdate :: !(Maybe CascadeAction)
- fcOnDelete :: !(Maybe CascadeAction)
- data ForeignDef = ForeignDef {
- foreignRefTableHaskell :: !EntityNameHS
- foreignRefTableDBName :: !EntityNameDB
- foreignConstraintNameHaskell :: !ConstraintNameHS
- foreignConstraintNameDBName :: !ConstraintNameDB
- foreignFieldCascade :: !FieldCascade
- foreignFields :: ![(ForeignFieldDef, ForeignFieldDef)]
- foreignAttrs :: ![Attr]
- foreignNullable :: Bool
- foreignToPrimary :: Bool
- type ForeignFieldDef = (FieldNameHS, FieldNameDB)
- data CompositeDef = CompositeDef {
- compositeFields :: !(NonEmpty FieldDef)
- compositeAttrs :: ![Attr]
- data UniqueDef = UniqueDef {
- uniqueHaskell :: !ConstraintNameHS
- uniqueDBName :: !ConstraintNameDB
- uniqueFields :: !(NonEmpty (FieldNameHS, FieldNameDB))
- uniqueAttrs :: ![Attr]
- data EmbedFieldDef = EmbedFieldDef {
- emFieldDB :: FieldNameDB
- emFieldEmbed :: Maybe (Either SelfEmbed EntityNameHS)
- data EmbedEntityDef = EmbedEntityDef {}
- data ReferenceDef
- data FieldType
- data FieldAttr
- type Attr = Text
- type ExtraLine = [Text]
- data EntityIdDef
- data EntityDef
- data WhyNullable
- data IsNullable
- data Checkmark
- fieldAttrsContainsNullable :: [FieldAttr] -> IsNullable
- entitiesPrimary :: EntityDef -> NonEmpty FieldDef
- entityPrimary :: EntityDef -> Maybe CompositeDef
- keyAndEntityFields :: EntityDef -> NonEmpty FieldDef
- parseFieldAttrs :: [Text] -> [FieldAttr]
- isFieldNotGenerated :: FieldDef -> Bool
- isHaskellField :: FieldDef -> Bool
- noCascade :: FieldCascade
- renderFieldCascade :: FieldCascade -> Text
- renderCascadeAction :: CascadeAction -> Text
- data Statement = Statement {
- stmtFinalize :: IO ()
- stmtReset :: IO ()
- stmtExecute :: [PersistValue] -> IO Int64
- stmtQuery :: forall (m :: Type -> Type). MonadIO m => [PersistValue] -> Acquire (ConduitM () [PersistValue] m ())
- data InsertSqlResult
- type LogFunc = Loc -> LogSource -> LogLevel -> LogStr -> IO ()
- setFieldAttrs :: [FieldAttr] -> FieldDef -> FieldDef
- overFieldAttrs :: ([FieldAttr] -> [FieldAttr]) -> FieldDef -> FieldDef
- addFieldAttr :: FieldAttr -> FieldDef -> FieldDef
- isFieldNullable :: FieldDef -> IsNullable
- isFieldMaybe :: FieldDef -> Bool
- getEntityUniques :: EntityDef -> [UniqueDef]
- getEntityHaskellName :: EntityDef -> EntityNameHS
- getEntityDBName :: EntityDef -> EntityNameDB
- getEntityExtra :: EntityDef -> Map Text [[Text]]
- setEntityDBName :: EntityNameDB -> EntityDef -> EntityDef
- getEntityComments :: EntityDef -> Maybe Text
- getEntityForeignDefs :: EntityDef -> [ForeignDef]
- getEntityFields :: EntityDef -> [FieldDef]
- getEntityFieldsDatabase :: EntityDef -> [FieldDef]
- isEntitySum :: EntityDef -> Bool
- getEntityId :: EntityDef -> EntityIdDef
- getEntityIdField :: EntityDef -> Maybe FieldDef
- setEntityId :: FieldDef -> EntityDef -> EntityDef
- setEntityIdDef :: EntityIdDef -> EntityDef -> EntityDef
- getEntityKeyFields :: EntityDef -> NonEmpty FieldDef
- overEntityFields :: ([FieldDef] -> [FieldDef]) -> EntityDef -> EntityDef
- data SomePersistField = PersistField a => SomePersistField a
- newtype OverflowNatural = OverflowNatural {}
- class PersistField a where
- toPersistValue :: a -> PersistValue
- fromPersistValue :: PersistValue -> Either Text a
- class SymbolToField (sym :: Symbol) rec typ | sym rec -> typ where
- symbolToField :: EntityField rec typ
- data Entity record = Entity {}
- data FilterValue typ where
- FilterValue :: forall typ. typ -> FilterValue typ
- FilterValues :: forall typ. [typ] -> FilterValue typ
- UnsafeValue :: forall a typ. PersistField a => a -> FilterValue typ
- type family BackendSpecificUpdate backend record
- class (PersistField (Key record), ToJSON (Key record), FromJSON (Key record), Show (Key record), Read (Key record), Eq (Key record), Ord (Key record)) => PersistEntity record where
- type PersistEntityBackend record
- data Key record
- data EntityField record :: Type -> Type
- data Unique record
- keyToValues :: Key record -> [PersistValue]
- keyFromValues :: [PersistValue] -> Either Text (Key record)
- persistIdField :: EntityField record (Key record)
- entityDef :: proxy record -> EntityDef
- persistFieldDef :: EntityField record typ -> FieldDef
- toPersistFields :: record -> [SomePersistField]
- fromPersistValues :: [PersistValue] -> Either Text record
- persistUniqueKeys :: record -> [Unique record]
- persistUniqueToFieldNames :: Unique record -> NonEmpty (FieldNameHS, FieldNameDB)
- persistUniqueToValues :: Unique record -> [PersistValue]
- fieldLens :: EntityField record field -> forall (f :: Type -> Type). Functor f => (field -> f field) -> Entity record -> f (Entity record)
- keyFromRecordM :: Maybe (record -> Key record)
- type family PersistEntityBackend record
- data family Key record
- data family EntityField record :: Type -> Type
- data family Unique record
- entityValues :: PersistEntity record => Entity record -> [PersistValue]
- keyValueEntityToJSON :: (PersistEntity record, ToJSON record) => Entity record -> Value
- keyValueEntityFromJSON :: (PersistEntity record, FromJSON record) => Value -> Parser (Entity record)
- entityIdToJSON :: (PersistEntity record, ToJSON record) => Entity record -> Value
- entityIdFromJSON :: (PersistEntity record, FromJSON record) => Value -> Parser (Entity record)
- toPersistValueJSON :: ToJSON a => a -> PersistValue
- fromPersistValueJSON :: FromJSON a => PersistValue -> Either Text a
- class (Show (BackendKey backend), Read (BackendKey backend), Eq (BackendKey backend), Ord (BackendKey backend), PersistStoreRead backend, PersistField (BackendKey backend), ToJSON (BackendKey backend), FromJSON (BackendKey backend)) => PersistStoreWrite backend where
- insertMany :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record backend) => [record] -> ReaderT backend m [Key record]
- repsert :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record backend) => Key record -> record -> ReaderT backend m ()
- repsertMany :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record backend) => [(Key record, record)] -> ReaderT backend m ()
- replace :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record backend) => Key record -> record -> ReaderT backend m ()
- updateGet :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record backend) => Key record -> [Update record] -> ReaderT backend m record
- class (Show (BackendKey backend), Read (BackendKey backend), Eq (BackendKey backend), Ord (BackendKey backend), PersistCore backend, PersistField (BackendKey backend), ToJSON (BackendKey backend), FromJSON (BackendKey backend)) => PersistStoreRead backend
- class PersistCore backend where
- data BackendKey backend
- data family BackendKey backend
- class (PersistEntity record, PersistEntityBackend record ~ backend, PersistCore backend) => ToBackendKey backend record where
- toBackendKey :: Key record -> BackendKey backend
- fromBackendKey :: BackendKey backend -> Key record
- type PersistRecordBackend record backend = (PersistEntity record, PersistEntityBackend record ~ BaseBackend backend)
- class BackendCompatible sup sub where
- projectBackend :: sub -> sup
- class HasPersistBackend backend => IsPersistBackend backend
- class HasPersistBackend backend where
- type BaseBackend backend
- persistBackend :: backend -> BaseBackend backend
- type family BaseBackend backend
- withBaseBackend :: forall backend (m :: Type -> Type) a. HasPersistBackend backend => ReaderT (BaseBackend backend) m a -> ReaderT backend m a
- withCompatibleBackend :: forall sup sub (m :: Type -> Type) a. BackendCompatible sup sub => ReaderT sup m a -> ReaderT sub m a
- liftPersist :: (MonadIO m, MonadReader backend m) => ReaderT backend IO b -> m b
- getJust :: forall record backend (m :: Type -> Type). (PersistStoreRead backend, PersistRecordBackend record backend, MonadIO m) => Key record -> ReaderT backend m record
- getJustEntity :: forall record backend (m :: Type -> Type). (PersistEntityBackend record ~ BaseBackend backend, MonadIO m, PersistEntity record, PersistStoreRead backend) => Key record -> ReaderT backend m (Entity record)
- belongsTo :: forall ent1 ent2 backend (m :: Type -> Type). (PersistStoreRead backend, PersistEntity ent1, PersistRecordBackend ent2 backend, MonadIO m) => (ent1 -> Maybe (Key ent2)) -> ent1 -> ReaderT backend m (Maybe ent2)
- belongsToJust :: forall ent1 ent2 backend (m :: Type -> Type). (PersistStoreRead backend, PersistEntity ent1, PersistRecordBackend ent2 backend, MonadIO m) => (ent1 -> Key ent2) -> ent1 -> ReaderT backend m ent2
- insertEntity :: forall e backend (m :: Type -> Type). (PersistStoreWrite backend, PersistRecordBackend e backend, MonadIO m) => e -> ReaderT backend m (Entity e)
- insertRecord :: forall record backend (m :: Type -> Type). (PersistEntityBackend record ~ BaseBackend backend, PersistEntity record, MonadIO m, PersistStoreWrite backend) => record -> ReaderT backend m record
- data SqlBackend
- class PersistEntity record => AtLeastOneUniqueKey record where
- requireUniquesP :: record -> NonEmpty (Unique record)
- type MultipleUniqueKeysError ty = ((('Text "The entity " :<>: 'ShowType ty) :<>: 'Text " has multiple unique keys.") :$$: ('Text "The function you are trying to call requires only a single " :<>: 'Text "unique key.")) :$$: (('Text "There is probably a variant of the function with 'By' " :<>: 'Text "appended that will allow you to select a unique key ") :<>: 'Text "for the operation.")
- type NoUniqueKeysError ty = (('Text "The entity " :<>: 'ShowType ty) :<>: 'Text " does not have any unique keys.") :$$: ('Text "The function you are trying to call requires a unique key " :<>: 'Text "to be defined on the entity.")
- class PersistEntity record => OnlyOneUniqueKey record where
- onlyUniqueP :: record -> Unique record
- class (PersistUniqueRead backend, PersistStoreWrite backend) => PersistUniqueWrite backend where
- deleteBy :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record backend) => Unique record -> ReaderT backend m ()
- insertUnique :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record backend) => record -> ReaderT backend m (Maybe (Key record))
- upsert :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record backend, OnlyOneUniqueKey record) => record -> [Update record] -> ReaderT backend m (Entity record)
- upsertBy :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record backend) => Unique record -> record -> [Update record] -> ReaderT backend m (Entity record)
- putMany :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record backend) => [record] -> ReaderT backend m ()
- class PersistStoreRead backend => PersistUniqueRead backend
- onlyOneUniqueDef :: (OnlyOneUniqueKey record, Monad proxy) => proxy record -> UniqueDef
- insertBy :: forall record backend (m :: Type -> Type). (MonadIO m, PersistUniqueWrite backend, PersistRecordBackend record backend, AtLeastOneUniqueKey record) => record -> ReaderT backend m (Either (Entity record) (Key record))
- insertUniqueEntity :: forall record backend (m :: Type -> Type). (MonadIO m, PersistRecordBackend record backend, PersistUniqueWrite backend) => record -> ReaderT backend m (Maybe (Entity record))
- onlyUnique :: forall record backend (m :: Type -> Type). (MonadIO m, PersistUniqueWrite backend, PersistRecordBackend record backend, OnlyOneUniqueKey record) => record -> ReaderT backend m (Unique record)
- getByValue :: forall record (m :: Type -> Type) backend. (MonadIO m, PersistUniqueRead backend, PersistRecordBackend record backend, AtLeastOneUniqueKey record) => record -> ReaderT backend m (Maybe (Entity record))
- replaceUnique :: forall record backend (m :: Type -> Type). (MonadIO m, Eq (Unique record), PersistRecordBackend record backend, PersistUniqueWrite backend) => Key record -> record -> ReaderT backend m (Maybe (Unique record))
- checkUnique :: forall record backend (m :: Type -> Type). (MonadIO m, PersistRecordBackend record backend, PersistUniqueRead backend) => record -> ReaderT backend m (Maybe (Unique record))
- checkUniqueUpdateable :: forall record backend (m :: Type -> Type). (MonadIO m, PersistRecordBackend record backend, PersistUniqueRead backend) => Entity record -> ReaderT backend m (Maybe (Unique record))
- class (PersistQueryRead backend, PersistStoreWrite backend) => PersistQueryWrite backend
- class (PersistCore backend, PersistStoreRead backend) => PersistQueryRead backend where
- selectSourceRes :: forall record (m1 :: Type -> Type) (m2 :: Type -> Type). (PersistRecordBackend record backend, MonadIO m1, MonadIO m2) => [Filter record] -> [SelectOpt record] -> ReaderT backend m1 (Acquire (ConduitM () (Entity record) m2 ()))
- selectKeysRes :: forall (m1 :: Type -> Type) (m2 :: Type -> Type) record. (MonadIO m1, MonadIO m2, PersistRecordBackend record backend) => [Filter record] -> [SelectOpt record] -> ReaderT backend m1 (Acquire (ConduitM () (Key record) m2 ()))
- selectKeys :: forall record backend (m :: Type -> Type). (PersistQueryRead backend, MonadResource m, PersistRecordBackend record backend, MonadReader backend m) => [Filter record] -> [SelectOpt record] -> ConduitM () (Key record) m ()
- class (PersistStoreWrite backend, PersistEntity record, BaseBackend backend ~ PersistEntityBackend record) => DeleteCascade record backend where
- deleteCascadeWhere :: forall record backend (m :: Type -> Type). (MonadIO m, DeleteCascade record backend, PersistQueryWrite backend) => [Filter record] -> ReaderT backend m ()
- type PersistStore a = PersistStoreWrite a
- type PersistUnique a = PersistUniqueWrite a
- type IsSqlBackend backend = (IsPersistBackend backend, BaseBackend backend ~ SqlBackend)
- type SqlWriteT (m :: Type -> Type) a = forall backend. SqlBackendCanWrite backend => ReaderT backend m a
- type SqlReadT (m :: Type -> Type) a = forall backend. SqlBackendCanRead backend => ReaderT backend m a
- type SqlBackendCanWrite backend = (SqlBackendCanRead backend, PersistQueryWrite backend, PersistStoreWrite backend, PersistUniqueWrite backend)
- type SqlBackendCanRead backend = (BackendCompatible SqlBackend backend, PersistQueryRead backend, PersistStoreRead backend, PersistUniqueRead backend)
- newtype SqlWriteBackend = SqlWriteBackend {}
- newtype SqlReadBackend = SqlReadBackend {}
- writeToUnknown :: forall (m :: Type -> Type) a. Monad m => ReaderT SqlWriteBackend m a -> ReaderT SqlBackend m a
- readToWrite :: forall (m :: Type -> Type) a. Monad m => ReaderT SqlReadBackend m a -> ReaderT SqlWriteBackend m a
- readToUnknown :: forall (m :: Type -> Type) a. Monad m => ReaderT SqlReadBackend m a -> ReaderT SqlBackend m a
- newtype Single a = Single {
- unSingle :: a
- data ConnectionPoolConfig = ConnectionPoolConfig {}
- type ConnectionPool = Pool SqlBackend
- type SqlPersistM = SqlPersistT (NoLoggingT (ResourceT IO))
- type SqlPersistT = ReaderT SqlBackend
- data PersistentSqlException
- data ColumnReference = ColumnReference {}
- data Column = Column {
- cName :: !FieldNameDB
- cNull :: !Bool
- cSqlType :: !SqlType
- cDefault :: !(Maybe Text)
- cGenerated :: !(Maybe Text)
- cDefaultConstraintName :: !(Maybe ConstraintNameDB)
- cMaxLen :: !(Maybe Integer)
- cReference :: !(Maybe ColumnReference)
- defaultConnectionPoolConfig :: ConnectionPoolConfig
- data BackendSpecificOverrides
- getBackendSpecificForeignKeyName :: BackendSpecificOverrides -> Maybe (EntityNameDB -> FieldNameDB -> ConstraintNameDB)
- setBackendSpecificForeignKeyName :: (EntityNameDB -> FieldNameDB -> ConstraintNameDB) -> BackendSpecificOverrides -> BackendSpecificOverrides
- emptyBackendSpecificOverrides :: BackendSpecificOverrides
- defaultAttribute :: [FieldAttr] -> Maybe Text
- mkColumns :: [EntityDef] -> EntityDef -> BackendSpecificOverrides -> ([Column], [UniqueDef], [ForeignDef])
- toJsonText :: ToJSON j => j -> Text
- class PersistField a => PersistFieldSql a where
- newtype EntityWithPrefix (prefix :: Symbol) record = EntityWithPrefix {
- unEntityWithPrefix :: Entity record
- class RawSql a where
- rawSqlCols :: (Text -> Text) -> a -> (Int, [Text])
- rawSqlColCountReason :: a -> String
- rawSqlProcessRow :: [PersistValue] -> Either Text a
- unPrefix :: forall (prefix :: Symbol) record. EntityWithPrefix prefix record -> Entity record
- rawQuery :: forall (m :: Type -> Type) env. (MonadResource m, MonadReader env m, BackendCompatible SqlBackend env) => Text -> [PersistValue] -> ConduitM () [PersistValue] m ()
- rawQueryRes :: forall (m1 :: Type -> Type) (m2 :: Type -> Type) env. (MonadIO m1, MonadIO m2, BackendCompatible SqlBackend env) => Text -> [PersistValue] -> ReaderT env m1 (Acquire (ConduitM () [PersistValue] m2 ()))
- rawExecute :: forall (m :: Type -> Type) backend. (MonadIO m, BackendCompatible SqlBackend backend) => Text -> [PersistValue] -> ReaderT backend m ()
- rawExecuteCount :: forall (m :: Type -> Type) backend. (MonadIO m, BackendCompatible SqlBackend backend) => Text -> [PersistValue] -> ReaderT backend m Int64
- getStmtConn :: SqlBackend -> Text -> IO Statement
- rawSql :: forall a (m :: Type -> Type) backend. (RawSql a, MonadIO m, BackendCompatible SqlBackend backend) => Text -> [PersistValue] -> ReaderT backend m [a]
- runSqlPool :: forall backend m a. (MonadUnliftIO m, BackendCompatible SqlBackend backend) => ReaderT backend m a -> Pool backend -> m a
- runSqlPoolWithIsolation :: forall backend m a. (MonadUnliftIO m, BackendCompatible SqlBackend backend) => ReaderT backend m a -> Pool backend -> IsolationLevel -> m a
- runSqlPoolNoTransaction :: forall backend m a. (MonadUnliftIO m, BackendCompatible SqlBackend backend) => ReaderT backend m a -> Pool backend -> Maybe IsolationLevel -> m a
- runSqlPoolWithHooks :: forall backend m a before after onException. (MonadUnliftIO m, BackendCompatible SqlBackend backend) => ReaderT backend m a -> Pool backend -> Maybe IsolationLevel -> (backend -> m before) -> (backend -> m after) -> (backend -> SomeException -> m onException) -> m a
- runSqlPoolWithExtensibleHooks :: forall backend m a. (MonadUnliftIO m, BackendCompatible SqlBackend backend) => ReaderT backend m a -> Pool backend -> Maybe IsolationLevel -> SqlPoolHooks m backend -> m a
- acquireSqlConn :: (MonadReader backend m, BackendCompatible SqlBackend backend) => m (Acquire backend)
- acquireSqlConnWithIsolation :: (MonadReader backend m, BackendCompatible SqlBackend backend) => IsolationLevel -> m (Acquire backend)
- runSqlConn :: forall backend m a. (MonadUnliftIO m, BackendCompatible SqlBackend backend) => ReaderT backend m a -> backend -> m a
- runSqlConnWithIsolation :: forall backend m a. (MonadUnliftIO m, BackendCompatible SqlBackend backend) => ReaderT backend m a -> backend -> IsolationLevel -> m a
- runSqlPersistM :: BackendCompatible SqlBackend backend => ReaderT backend (NoLoggingT (ResourceT IO)) a -> backend -> IO a
- runSqlPersistMPool :: BackendCompatible SqlBackend backend => ReaderT backend (NoLoggingT (ResourceT IO)) a -> Pool backend -> IO a
- liftSqlPersistMPool :: forall backend m a. (MonadIO m, BackendCompatible SqlBackend backend) => ReaderT backend (NoLoggingT (ResourceT IO)) a -> Pool backend -> m a
- withSqlPool :: forall backend m a. (MonadLoggerIO m, MonadUnliftIO m, BackendCompatible SqlBackend backend) => (LogFunc -> IO backend) -> Int -> (Pool backend -> m a) -> m a
- withSqlPoolWithConfig :: forall backend m a. (MonadLoggerIO m, MonadUnliftIO m, BackendCompatible SqlBackend backend) => (LogFunc -> IO backend) -> ConnectionPoolConfig -> (Pool backend -> m a) -> m a
- createSqlPool :: forall backend m. (MonadLoggerIO m, MonadUnliftIO m, BackendCompatible SqlBackend backend) => (LogFunc -> IO backend) -> Int -> m (Pool backend)
- createSqlPoolWithConfig :: (MonadLoggerIO m, MonadUnliftIO m, BackendCompatible SqlBackend backend) => (LogFunc -> IO backend) -> ConnectionPoolConfig -> m (Pool backend)
- withSqlConn :: forall backend m a. (MonadUnliftIO m, MonadLoggerIO m, BackendCompatible SqlBackend backend) => (LogFunc -> IO backend) -> (backend -> m a) -> m a
- close' :: BackendCompatible SqlBackend backend => backend -> IO ()
- withRawQuery :: forall (m :: Type -> Type) a. MonadIO m => Text -> [PersistValue] -> ConduitM [PersistValue] Void IO a -> ReaderT SqlBackend m a
- toSqlKey :: ToBackendKey SqlBackend record => Int64 -> Key record
- fromSqlKey :: ToBackendKey SqlBackend record => Key record -> Int64
- getTableName :: forall record (m :: Type -> Type) backend. (PersistEntity record, BackendCompatible SqlBackend backend, Monad m) => record -> ReaderT backend m Text
- tableDBName :: PersistEntity record => record -> EntityNameDB
- getFieldName :: forall record typ (m :: Type -> Type) backend. (PersistEntity record, PersistEntityBackend record ~ SqlBackend, BackendCompatible SqlBackend backend, Monad m) => EntityField record typ -> ReaderT backend m Text
- fieldDBName :: PersistEntity record => EntityField record typ -> FieldNameDB
- data FilterTablePrefix
- filterClause :: PersistEntity val => Maybe FilterTablePrefix -> SqlBackend -> [Filter val] -> Text
- filterClauseWithVals :: PersistEntity val => Maybe FilterTablePrefix -> SqlBackend -> [Filter val] -> (Text, [PersistValue])
- orderClause :: PersistEntity val => Maybe FilterTablePrefix -> SqlBackend -> [SelectOpt val] -> Text
- decorateSQLWithLimitOffset :: Text -> (Int, Int) -> Text -> Text
- newtype PersistUnsafeMigrationException = PersistUnsafeMigrationException [(Bool, Sql)]
- type Migration = WriterT [Text] (WriterT CautiousMigration (ReaderT SqlBackend IO)) ()
- type CautiousMigration = [(Bool, Sql)]
- type Sql = Text
- parseMigration :: forall (m :: Type -> Type). (HasCallStack, MonadIO m) => Migration -> ReaderT SqlBackend m (Either [Text] CautiousMigration)
- parseMigration' :: forall (m :: Type -> Type). (HasCallStack, MonadIO m) => Migration -> ReaderT SqlBackend m CautiousMigration
- printMigration :: forall (m :: Type -> Type). (HasCallStack, MonadIO m) => Migration -> ReaderT SqlBackend m ()
- showMigration :: forall (m :: Type -> Type). (HasCallStack, MonadIO m) => Migration -> ReaderT SqlBackend m [Text]
- getMigration :: forall (m :: Type -> Type). (MonadIO m, HasCallStack) => Migration -> ReaderT SqlBackend m [Sql]
- runMigration :: forall (m :: Type -> Type). MonadIO m => Migration -> ReaderT SqlBackend m ()
- runMigrationQuiet :: forall (m :: Type -> Type). MonadIO m => Migration -> ReaderT SqlBackend m [Text]
- runMigrationSilent :: forall (m :: Type -> Type). MonadUnliftIO m => Migration -> ReaderT SqlBackend m [Text]
- runMigrationUnsafe :: forall (m :: Type -> Type). MonadIO m => Migration -> ReaderT SqlBackend m ()
- runMigrationUnsafeQuiet :: forall (m :: Type -> Type). (HasCallStack, MonadIO m) => Migration -> ReaderT SqlBackend m [Text]
- migrate :: [EntityDef] -> EntityDef -> Migration
- reportError :: Text -> Migration
- reportErrors :: [Text] -> Migration
- addMigration :: Bool -> Sql -> Migration
- addMigrations :: CautiousMigration -> Migration
- runSqlCommand :: SqlPersistT IO () -> Migration
- transactionSave :: forall (m :: Type -> Type). MonadIO m => ReaderT SqlBackend m ()
- transactionSaveWithIsolation :: forall (m :: Type -> Type). MonadIO m => IsolationLevel -> ReaderT SqlBackend m ()
- transactionUndo :: forall (m :: Type -> Type). MonadIO m => ReaderT SqlBackend m ()
- transactionUndoWithIsolation :: forall (m :: Type -> Type). MonadIO m => IsolationLevel -> ReaderT SqlBackend m ()
Documentation
selectOne :: (MonadSqlQuery m, SqlSelect a r) => SqlQuery a -> m (Maybe r) Source #
Classy version of selectOne
update :: (MonadSqlQuery m, PersistEntity val, BackendCompatible SqlBackend (PersistEntityBackend val)) => (SqlExpr (Entity val) -> SqlQuery ()) -> m () Source #
Classy version of update
renderQuerySelect :: (MonadSqlQuery m, SqlSelect a r) => SqlQuery a -> m (Text, [PersistValue]) Source #
deleteWhere :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => [Filter record] -> m () #
The lifted version of deleteWhere
get :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => Key record -> m (Maybe record) #
The lifted version of get
getBy :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => Unique record -> m (Maybe (Entity record)) #
The lifted version of getBy
getEntity :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => Key record -> m (Maybe (Entity record)) #
The lifted version of getEntity
getMany :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => [Key record] -> m (Map (Key record) record) #
The lifted version of getMany
insert :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => record -> m (Key record) #
The lifted version of insert
insert_ :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => record -> m () #
The lifted version of insert_
insertKey :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => Key record -> record -> m () #
The lifted version of insertKey
insertMany_ :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => [record] -> m () #
The lifted version of insertMany_
insertEntityMany :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => [Entity record] -> m () #
The lifted version of insertEntityMany
selectFirst :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => [Filter record] -> [SelectOpt record] -> m (Maybe (Entity record)) #
The lifted version of selectFirst
updateWhere :: (PersistRecordBackend record SqlBackend, Typeable record, MonadSqlQuery m) => [Filter record] -> [Update record] -> m () #
The lifted version of updateWhere
associateJoin :: forall e1 e0. Ord (Key e0) => [(Entity e0, e1)] -> Map (Key e0) (e0, [e1]) #
Avoid N+1 queries and join entities into a map structure.
This function is useful to call on the result of a single JOIN
. For
example, suppose you have this query:
getFoosAndNestedBarsFromParent :: ParentId -> SqlPersistT IO [(Entity Foo, Maybe (Entity Bar))] getFoosAndNestedBarsFromParent parentId =select
$ do (foo :& bar) <- from $ tableFoo
Bar`LeftOuterJoin`
table`on`
do \(foo :& bar) -> foo ^. FooId ==. bar ?. BarFooId where_ $ foo ^. FooParentId ==. val parentId pure (foo, bar)
This is a natural result type for SQL - a list of tuples. However, it's not
what we usually want in Haskell - each Foo
in the list will be represented
multiple times, once for each Bar
.
We can write
and it will translate it into a fmap
associateJoin
Map
that is keyed on the Key
of the left Entity
, and the value is a tuple of
the entity's value as well as the list of each coresponding entity.
getFoosAndNestedBarsFromParentHaskellese :: ParentId -> SqlPersistT (Map (Key Foo) (Foo, [Maybe (Entity Bar)])) getFoosAndNestedBarsFromParentHaskellese parentId =fmap
associateJoin
$ getFoosdAndNestedBarsFromParent parentId
What if you have multiple joins?
Let's use associateJoin
with a *two* join query.
userPostComments :: SqlQuery (SqlExpr (Entity User, Entity Post, Entity Comment)) userPostsComment = do (u :& p :& c) <- from $ tableUser
Post`InnerJoin`
tableon
do \(u :& p) -> u ^. UserId ==. p ^. PostUserId`InnerJoin`
table @Comment`on`
do \(_ :& p :& c) -> p ^. PostId ==. c ^. CommentPostId pure (u, p, c)
This query returns a User, with all of the users Posts, and then all of the Comments on that post.
First, we *nest* the tuple.
nest :: (a, b, c) -> (a, (b, c)) nest (a, b, c) = (a, (b, c))
This makes the return of the query conform to the input expected from
associateJoin
.
nestedUserPostComments :: SqlPersistT IO [(Entity User, (Entity Post, Entity Comment))] nestedUserPostComments = fmap nest $ select userPostsComments
Now, we can call associateJoin
on it.
associateUsers :: [(Entity User, (Entity Post, Entity Comment))] -> Map UserId (User, [(Entity Post, Entity Comment)]) associateUsers = associateJoin
Next, we'll use the Functor
instances for Map
and tuple to call
associateJoin
on the [(Entity Post, Entity Comment)]
.
associatePostsAndComments :: Map UserId (User, [(Entity Post, Entity Comment)]) -> Map UserId (User, Map PostId (Post, [Entity Comment])) associatePostsAndComments = fmap (fmap associateJoin)
For more reading on this topic, see this Foxhound Systems blog post.
Since: esqueleto-3.1.2
deleteKey :: forall backend val (m :: Type -> Type). (PersistStore backend, BaseBackend backend ~ PersistEntityBackend val, MonadIO m, PersistEntity val) => Key val -> ReaderT backend m () #
valJ :: PersistField (Key entity) => Value (Key entity) -> SqlExpr (Value (Key entity)) #
valJ
is like val
but for something that is already a Value
. The use
case it was written for was, given a Value
lift the Key
for that Value
into the query expression in a type safe way. However, the implementation is
more generic than that so we call it valJ
.
Its important to note that the input entity and the output entity are constrained to be the same by the type signature on the function (https://github.com/prowdsponsor/esqueleto/pull/69).
Since: esqueleto-1.4.2
valkey :: (ToBackendKey SqlBackend entity, PersistField (Key entity)) => Int64 -> SqlExpr (Value (Key entity)) #
valkey i =
(https://github.com/prowdsponsor/esqueleto/issues/9).val
. toSqlKey
insertSelectCount :: forall (m :: Type -> Type) a backend. (MonadIO m, PersistEntity a, SqlBackendCanWrite backend) => SqlQuery (SqlExpr (Insertion a)) -> ReaderT backend m Int64 #
Insert a PersistField
for every selected value, return the count afterward
insertSelect :: forall (m :: Type -> Type) a backend. (MonadIO m, PersistEntity a, SqlBackendCanWrite backend) => SqlQuery (SqlExpr (Insertion a)) -> ReaderT backend m () #
Insert a PersistField
for every selected value.
Since: esqueleto-2.4.2
:: forall a r backend (m :: Type -> Type). (SqlSelect a r, BackendCompatible SqlBackend backend, Monad m) | |
=> SqlQuery a | The SQL query you want to render. |
-> ReaderT backend m (Text, [PersistValue]) |
Renders a SqlQuery
into a Text
value along with the list of
PersistValue
s that would be supplied to the database for ?
placeholders.
Since: esqueleto-3.1.1
:: forall a r backend (m :: Type -> Type). (SqlSelect a r, BackendCompatible SqlBackend backend, Monad m) | |
=> SqlQuery a | The SQL query you want to render. |
-> ReaderT backend m (Text, [PersistValue]) |
Renders a SqlQuery
into a Text
value along with the list of
PersistValue
s that would be supplied to the database for ?
placeholders.
Since: esqueleto-3.1.1
:: forall a r backend (m :: Type -> Type). (SqlSelect a r, BackendCompatible SqlBackend backend, Monad m) | |
=> SqlQuery a | The SQL query you want to render. |
-> ReaderT backend m (Text, [PersistValue]) |
Renders a SqlQuery
into a Text
value along with the list of
PersistValue
s that would be supplied to the database for ?
placeholders.
Since: esqueleto-3.1.1
:: forall a r backend (m :: Type -> Type). (SqlSelect a r, BackendCompatible SqlBackend backend, Monad m) | |
=> Mode | |
-> SqlQuery a | The SQL query you want to render. |
-> ReaderT backend m (Text, [PersistValue]) |
Renders a SqlQuery
into a Text
value along with the list of
PersistValue
s that would be supplied to the database for ?
placeholders.
You must ensure that the Mode
you pass to this function corresponds with
the actual SqlQuery
. If you pass a query that uses incompatible features
(like an INSERT
statement with a SELECT
mode) then you'll get a weird
result.
Since: esqueleto-3.1.1
updateCount :: forall (m :: Type -> Type) val backend. (MonadIO m, PersistEntity val, BackendCompatible SqlBackend (PersistEntityBackend val), SqlBackendCanWrite backend) => (SqlExpr (Entity val) -> SqlQuery ()) -> ReaderT backend m Int64 #
Same as update
, but returns the number of rows affected.
deleteCount :: forall (m :: Type -> Type) backend. (MonadIO m, SqlBackendCanWrite backend) => SqlQuery () -> ReaderT backend m Int64 #
Same as delete
, but returns the number of rows affected.
selectSource :: forall a r backend (m :: Type -> Type). (SqlSelect a r, BackendCompatible SqlBackend backend, IsPersistBackend backend, PersistQueryRead backend, PersistStoreRead backend, PersistUniqueRead backend, MonadResource m) => SqlQuery a -> ConduitT () r (ReaderT backend m) () #
Execute an esqueleto
SELECT
query inside persistent
's
SqlPersistT
monad and return a Source
of rows.
from :: From a => (a -> SqlQuery b) -> SqlQuery b #
FROM
clause: bring entities into scope.
Note that this function will be replaced by the one in
Database.Esqueleto.Experimental in version 4.0.0.0 of the library. The
Experimental
module has a dramatically improved means for introducing
tables and entities that provides more power and less potential for runtime
errors.
This function internally uses two type classes in order to provide some flexibility of how you may call it. Internally we refer to these type classes as the two different magics.
The innermost magic allows you to use from
with the
following types:
expr (Entity val)
, which brings a single entity into scope.expr (Maybe (Entity val))
, which brings a single entity that may beNULL
into scope. Used forOUTER JOIN
s.- A
JOIN
of any other two types allowed by the innermost magic, where aJOIN
may be anInnerJoin
, aCrossJoin
, aLeftOuterJoin
, aRightOuterJoin
, or aFullOuterJoin
. TheJOINs
have left fixity.
The outermost magic allows you to use from
on any tuples of
types supported by innermost magic (and also tuples of tuples,
and so on), up to 8-tuples.
Note that using from
for the same entity twice does work and
corresponds to a self-join. You don't even need to use two
different calls to from
, you may use a JOIN
or a tuple.
The following are valid examples of uses of from
(the types
of the arguments of the lambda are inside square brackets):
from
$ \person -> ...from
$ \(person, blogPost) -> ...from
$ \(p `LeftOuterJoin
` mb) -> ...from
$ \(p1 `InnerJoin
` f `InnerJoin
` p2) -> ...from
$ \((p1 `InnerJoin
` f) `InnerJoin
` p2) -> ...
The types of the arguments to the lambdas above are, respectively:
person :: ( Esqueleto query expr backend , PersistEntity Person , PersistEntityBackend Person ~ backend ) => expr (Entity Person) (person, blogPost) :: (...) => (expr (Entity Person), expr (Entity BlogPost)) (p `LeftOuterJoin
` mb) :: (...) => InnerJoin (expr (Entity Person)) (expr (Maybe (Entity BlogPost))) (p1 `InnerJoin
` f `InnerJoin
` p2) :: (...) => InnerJoin (InnerJoin (expr (Entity Person)) (expr (Entity Follow))) (expr (Entity Person)) (p1 `InnerJoin
` (f `InnerJoin
` p2)) :: :: (...) => InnerJoin (expr (Entity Person)) (InnerJoin (expr (Entity Follow)) (expr (Entity Person)))
Note that some backends may not support all kinds of JOIN
s.
when_ :: expr (Value Bool) -> () -> expr a -> (expr (Value Bool), expr a) #
Syntax sugar for case_
.
Since: esqueleto-2.1.2
toBaseId :: ToBaseId ent => SqlExpr (Value (Key ent)) -> SqlExpr (Value (Key (BaseEnt ent))) #
Convert an entity's key into another entity's.
This function is to be used when you change an entity's Id
to be
that of another entity. For example:
Bar barNum Int Foo bar BarId fooNum Int Primary bar
In this example, Bar is said to be the BaseEnt(ity), and Foo the child. To model this in Esqueleto, declare:
instance ToBaseId Foo where type BaseEnt Foo = Bar toBaseIdWitness barId = FooKey barId
Now you're able to write queries such as:
select
$from
$ (bar `InnerJoin
` foo) -> doon
(toBaseId
(foo^.
FooId)==.
bar^.
BarId) return (bar, foo)
Note: this function may be unsafe to use in conditions not like the one of the example above.
Since: esqueleto-2.4.3
case_ :: PersistField a => [(SqlExpr (Value Bool), SqlExpr (Value a))] -> SqlExpr (Value a) -> SqlExpr (Value a) #
CASE
statement. For example:
select $ return $case_
[when_
(exists
$from
$ \p -> dowhere_
(p^.
PersonName==.
val
"Mike"))then_
(sub_select
$from
$ \v -> do let sub =from
$ \c -> dowhere_
(c^.
PersonName==.
val
"Mike") return (c^.
PersonFavNum)where_
(v^.
PersonFavNum >.sub_select
sub) return $count
(v^.
PersonName) +.val
(1 :: Int)) ] (else_
$val
(-1))
This query is a bit complicated, but basically it checks if a person
named "Mike"
exists, and if that person does, run the subquery to find
out how many people have a ranking (by Fav Num) higher than "Mike"
.
NOTE: There are a few things to be aware about this statement.
- This only implements the full CASE statement, it does not implement the "simple" CASE statement.
- At least one
when_
andthen_
is mandatory otherwise it will emit an error. - The
else_
is also mandatory, unlike the SQL statement in which if theELSE
is omitted it will return aNULL
. You can reproduce this vianothing
.
Since: esqueleto-2.1.2
(<&>) :: SqlExpr (Insertion (a -> b)) -> SqlExpr (Value a) -> SqlExpr (Insertion b) #
Apply extra SqlExpr Value
arguments to a PersistField
constructor
(<#) :: (a -> b) -> SqlExpr (Value a) -> SqlExpr (Insertion b) #
Apply a PersistField
constructor to SqlExpr Value
arguments.
(/=.) :: (PersistEntity val, PersistField a) => EntityField val a -> SqlExpr (Value a) -> SqlExpr (Entity val) -> SqlExpr Update infixr 3 #
(*=.) :: (PersistEntity val, PersistField a) => EntityField val a -> SqlExpr (Value a) -> SqlExpr (Entity val) -> SqlExpr Update infixr 3 #
(-=.) :: (PersistEntity val, PersistField a) => EntityField val a -> SqlExpr (Value a) -> SqlExpr (Entity val) -> SqlExpr Update infixr 3 #
(+=.) :: (PersistEntity val, PersistField a) => EntityField val a -> SqlExpr (Value a) -> SqlExpr (Entity val) -> SqlExpr Update infixr 3 #
(=.) :: (PersistEntity val, PersistField typ) => EntityField val typ -> SqlExpr (Value typ) -> SqlExpr (Entity val) -> SqlExpr Update infixr 3 #
set :: PersistEntity val => SqlExpr (Entity val) -> [SqlExpr (Entity val) -> SqlExpr Update] -> SqlQuery () #
SET
clause used on UPDATE
s. Note that while it's not
a type error to use this function on a SELECT
, it will
most certainly result in a runtime error.
notIn :: PersistField typ => SqlExpr (Value typ) -> SqlExpr (ValueList typ) -> SqlExpr (Value Bool) #
NOT IN
operator.
in_ :: PersistField typ => SqlExpr (Value typ) -> SqlExpr (ValueList typ) -> SqlExpr (Value Bool) #
IN
operator. For example if you want to select all Person
s by a list
of IDs:
SELECT * FROM Person WHERE Person.id IN (?)
In esqueleto
, we may write the same query above as:
select $from
$ \person -> dowhere_
$ person^.
PersonId `in_
`valList
personIds return person
Where personIds
is of type [Key Person]
.
valList :: PersistField typ => [typ] -> SqlExpr (ValueList typ) #
Lift a list of constant value from Haskell-land to the query.
subList_select :: PersistField a => SqlQuery (SqlExpr (Value a)) -> SqlExpr (ValueList a) #
Execute a subquery SELECT
in an SqlExpression. Returns a
list of values.
castString :: (SqlString s, SqlString r) => SqlExpr (Value s) -> SqlExpr (Value r) #
Cast a string type into Text
. This function
is very useful if you want to use newtype
s, or if you want
to apply functions such as like
to strings of different
types.
Safety: This is a slightly unsafe function, especially if
you have defined your own instances of SqlString
. Also,
since Maybe
is an instance of SqlString
, it's possible
to turn a nullable value into a non-nullable one. Avoid
using this function if possible.
concat_ :: SqlString s => [SqlExpr (Value s)] -> SqlExpr (Value s) #
The CONCAT
function with a variable number of
parameters. Supported by MySQL and PostgreSQL.
ilike :: SqlString s => SqlExpr (Value s) -> SqlExpr (Value s) -> SqlExpr (Value Bool) infixr 2 #
ILIKE
operator (case-insensitive LIKE
).
Supported by PostgreSQL only.
Since: esqueleto-2.2.3
like :: SqlString s => SqlExpr (Value s) -> SqlExpr (Value s) -> SqlExpr (Value Bool) infixr 2 #
LIKE
operator.
right_ :: (SqlString s, Num a) => (SqlExpr (Value s), SqlExpr (Value a)) -> SqlExpr (Value s) #
RIGHT
function.
@since 3.3.0
left_ :: (SqlString s, Num a) => (SqlExpr (Value s), SqlExpr (Value a)) -> SqlExpr (Value s) #
LEFT
function.
@since 3.3.0
length_ :: (SqlString s, Num a) => SqlExpr (Value s) -> SqlExpr (Value a) #
LENGTH
function.
@since 3.3.0
coalesceDefault :: PersistField a => [SqlExpr (Value (Maybe a))] -> SqlExpr (Value a) -> SqlExpr (Value a) #
Like coalesce
, but takes a non-nullable SqlExpression
placed at the end of the SqlExpression list, which guarantees
a non-NULL result.
Since: esqueleto-1.4.3
coalesce :: PersistField a => [SqlExpr (Value (Maybe a))] -> SqlExpr (Value (Maybe a)) #
COALESCE
function. Evaluates the arguments in order and
returns the value of the first non-NULL SqlExpression, or NULL
(Nothing) otherwise. Some RDBMSs (such as SQLite) require
at least two arguments; please refer to the appropriate
documentation.
Since: esqueleto-1.4.3
castNumM :: (Num a, Num b) => SqlExpr (Value (Maybe a)) -> SqlExpr (Value (Maybe b)) #
Same as castNum
, but for nullable values.
Since: esqueleto-2.2.9
castNum :: (Num a, Num b) => SqlExpr (Value a) -> SqlExpr (Value b) #
Allow a number of one type to be used as one of another type via an implicit cast. An explicit cast is not made, this function changes only the types on the Haskell side.
Caveat: Trying to use castNum
from Double
to Int
will not result in an integer, the original fractional
number will still be used! Use round_
, ceiling_
or
floor_
instead.
Safety: This operation is mostly safe due to the Num
constraint between the types and the fact that RDBMSs
usually allow numbers of different types to be used
interchangeably. However, there may still be issues with
the query not being accepted by the RDBMS or persistent
not being able to parse it.
Since: esqueleto-2.2.9
avg_ :: (PersistField a, PersistField b) => SqlExpr (Value a) -> SqlExpr (Value (Maybe b)) #
sum_ :: (PersistField a, PersistField b) => SqlExpr (Value a) -> SqlExpr (Value (Maybe b)) #
floor_ :: (PersistField a, Num a, PersistField b, Num b) => SqlExpr (Value a) -> SqlExpr (Value b) #
ceiling_ :: (PersistField a, Num a, PersistField b, Num b) => SqlExpr (Value a) -> SqlExpr (Value b) #
round_ :: (PersistField a, Num a, PersistField b, Num b) => SqlExpr (Value a) -> SqlExpr (Value b) #
between :: PersistField a => SqlExpr (Value a) -> (SqlExpr (Value a), SqlExpr (Value a)) -> SqlExpr (Value Bool) #
BETWEEN
.
@since: 3.1.0
(!=.) :: PersistField typ => SqlExpr (Value typ) -> SqlExpr (Value typ) -> SqlExpr (Value Bool) infix 4 #
(<.) :: PersistField typ => SqlExpr (Value typ) -> SqlExpr (Value typ) -> SqlExpr (Value Bool) infix 4 #
(<=.) :: PersistField typ => SqlExpr (Value typ) -> SqlExpr (Value typ) -> SqlExpr (Value Bool) infix 4 #
(>.) :: PersistField typ => SqlExpr (Value typ) -> SqlExpr (Value typ) -> SqlExpr (Value Bool) infix 4 #
(>=.) :: PersistField typ => SqlExpr (Value typ) -> SqlExpr (Value typ) -> SqlExpr (Value Bool) infix 4 #
(==.) :: PersistField typ => SqlExpr (Value typ) -> SqlExpr (Value typ) -> SqlExpr (Value Bool) infix 4 #
countDistinct :: Num a => SqlExpr (Value typ) -> SqlExpr (Value a) #
COUNT(DISTINCT x)
.
Since: esqueleto-2.4.1
isNothing :: PersistField typ => SqlExpr (Value (Maybe typ)) -> SqlExpr (Value Bool) #
IS NULL
comparison.
For IS NOT NULL
, you can negate this with not_
, as in not_ (isNothing (person ^. PersonAge))
Warning: Persistent and Esqueleto have different behavior for != Nothing
:
Haskell | SQL | |
---|---|---|
Persistent |
| IS NOT NULL |
Esqueleto |
| != NULL |
In SQL, = NULL
and != NULL
return NULL instead of true or false. For this reason, you very likely do not want to use
in Esqueleto.
You may find these !=.
Nothinghlint
rules helpful to enforce this:
- error: {lhs: v Database.Esqueleto.==. Database.Esqueleto.nothing, rhs: Database.Esqueleto.isNothing v, name: Use Esqueleto's isNothing} - error: {lhs: v Database.Esqueleto.==. Database.Esqueleto.val Nothing, rhs: Database.Esqueleto.isNothing v, name: Use Esqueleto's isNothing} - error: {lhs: v Database.Esqueleto.!=. Database.Esqueleto.nothing, rhs: not_ (Database.Esqueleto.isNothing v), name: Use Esqueleto's not isNothing} - error: {lhs: v Database.Esqueleto.!=. Database.Esqueleto.val Nothing, rhs: not_ (Database.Esqueleto.isNothing v), name: Use Esqueleto's not isNothing}
val :: PersistField typ => typ -> SqlExpr (Value typ) #
Lift a constant value from Haskell-land to the query.
(?.) :: (PersistEntity val, PersistField typ) => SqlExpr (Maybe (Entity val)) -> EntityField val typ -> SqlExpr (Value (Maybe typ)) #
Project a field of an entity that may be null.
withNonNull :: PersistField typ => SqlExpr (Value (Maybe typ)) -> (SqlExpr (Value typ) -> SqlQuery a) -> SqlQuery a #
Project an SqlExpression that may be null, guarding against null cases.
(^.) :: forall typ val. (PersistEntity val, PersistField typ) => SqlExpr (Entity val) -> EntityField val typ -> SqlExpr (Value typ) infixl 9 #
Project a field of an entity.
subSelectUnsafe :: PersistField a => SqlQuery (SqlExpr (Value a)) -> SqlExpr (Value a) #
Execute a subquery SELECT
in a SqlExpr
. This function is unsafe,
because it can throw runtime exceptions in two cases:
- If the query passed has 0 result rows, then it will return a
NULL
value. Thepersistent
parsing operations will fail on an unexpectedNULL
. - If the query passed returns more than one row, then the SQL engine will fail with an error like "More than one row returned by a subquery used as an expression".
This function is safe if you guarantee that exactly one row will be returned,
or if the result already has a Maybe
type for some reason.
For variants with the safety encoded already, see subSelect
and
subSelectMaybe
. For the most common safe use of this, see subSelectCount
.
Since: esqueleto-3.2.0
:: (BackendCompatible SqlBackend (PersistEntityBackend val1), PersistEntity val1, PersistEntity val2, PersistField a) | |
=> SqlExpr (Entity val2) | An expression representing the table you have access to now. |
-> EntityField val2 (Key val1) | The foreign key field on the table. |
-> (SqlExpr (Entity val1) -> SqlExpr (Value a)) | A function to extract a value from the foreign reference table. |
-> SqlExpr (Value a) |
Performs a sub-select using the given foreign key on the entity. This is useful to extract values that are known to be present by the database schema.
As an example, consider the following persistent definition:
User profile ProfileId Profile name Text
The following query will return the name of the user.
getUserWithName =select
$from
$ user ->pure
(user,subSelectForeign
user UserProfile (^. ProfileName)
Since: esqueleto-3.2.0
subSelectList :: PersistField a => SqlQuery (SqlExpr (Value a)) -> SqlExpr (ValueList a) #
Execute a subquery SELECT
in a SqlExpr
that returns a list. This is an
alias for subList_select
and is provided for symmetry with the other safe
subselect functions.
Since: esqueleto-3.2.0
subSelectCount :: (Num a, PersistField a) => SqlQuery ignored -> SqlExpr (Value a) #
Performs a COUNT
of the given query in a subSelect
manner. This is
always guaranteed to return a result value, and is completely safe.
Since: esqueleto-3.2.0
subSelectMaybe :: PersistField a => SqlQuery (SqlExpr (Value (Maybe a))) -> SqlExpr (Value (Maybe a)) #
Execute a subquery SELECT
in a SqlExpr
. This function is a shorthand
for the common
idiom, where you are calling
joinV
. subSelect
subSelect
on an expression that would be Maybe
already.
As an example, you would use this function when calling sum_
or max_
,
which have Maybe
in the result type (for a 0 row query).
Since: esqueleto-3.2.0
subSelect :: PersistField a => SqlQuery (SqlExpr (Value a)) -> SqlExpr (Value (Maybe a)) #
Execute a subquery SELECT
in a SqlExpr
. The query passed to this
function will only return a single result - it has a LIMIT 1
passed in to
the query to make it safe, and the return type is Maybe
to indicate that
the subquery might result in 0 rows.
If you find yourself writing
, then consider using
joinV
. subSelect
subSelectMaybe
.
If you're performing a countRows
, then you can use subSelectCount
which
is safe.
If you know that the subquery will always return exactly one row (eg
a foreign key constraint guarantees that you'll get exactly one row), then
consider subSelectUnsafe
, along with a comment explaining why it is safe.
Since: esqueleto-3.2.0
sub_select :: PersistField a => SqlQuery (SqlExpr (Value a)) -> SqlExpr (Value a) #
Execute a subquery SELECT
in an SqlExpression. Returns a
simple value so should be used only when the SELECT
query
is guaranteed to return just one row.
Deprecated in 3.2.0.
locking :: LockingKind -> SqlQuery () #
Add a locking clause to the query. Please read
LockingKind
documentation and your RDBMS manual.
If multiple calls to locking
are made on the same query,
the last one is used.
Since: esqueleto-2.2.7
distinctOnOrderBy :: [SqlExpr OrderBy] -> SqlQuery a -> SqlQuery a #
A convenience function that calls both distinctOn
and
orderBy
. In other words,
distinctOnOrderBy
[asc foo, desc bar, desc quux] $ do
...
is the same as:
distinctOn
[don foo, don bar, don quux] $ doorderBy
[asc foo, desc bar, desc quux] ...
Since: esqueleto-2.2.4
don :: SqlExpr (Value a) -> SqlExpr DistinctOn #
Erase an SqlExpression's type so that it's suitable to
be used by distinctOn
.
Since: esqueleto-2.2.4
distinctOn :: [SqlExpr DistinctOn] -> SqlQuery a -> SqlQuery a #
DISTINCT ON
. Change the current SELECT
into
SELECT DISTINCT ON (SqlExpressions)
. For example:
select $from
\foo ->distinctOn
[don
(foo ^. FooName),don
(foo ^. FooState)] $ do ...
You can also chain different calls to distinctOn
. The
above is equivalent to:
select $from
\foo ->distinctOn
[don
(foo ^. FooName)] $distinctOn
[don
(foo ^. FooState)] $ do ...
Each call to distinctOn
adds more SqlExpressions. Calls to
distinctOn
override any calls to distinct
.
Note that PostgreSQL requires the SqlExpressions on DISTINCT
ON
to be the first ones to appear on a ORDER BY
. This is
not managed automatically by esqueleto, keeping its spirit
of trying to be close to raw SQL.
Supported by PostgreSQL only.
Since: esqueleto-2.2.4
desc :: PersistField a => SqlExpr (Value a) -> SqlExpr OrderBy #
Descending order of this field or SqlExpression.
asc :: PersistField a => SqlExpr (Value a) -> SqlExpr OrderBy #
Ascending order of this field or SqlExpression.
orderBy :: [SqlExpr OrderBy] -> SqlQuery () #
ORDER BY
clause. See also asc
and desc
.
Multiple calls to orderBy
get concatenated on the final
query, including distinctOnOrderBy
.
groupBy :: ToSomeValues a => a -> SqlQuery () #
GROUP BY
clause. You can enclose multiple columns
in a tuple.
select $from
\(foo `InnerJoin
` bar) -> doon
(foo^.
FooBarId==.
bar^.
BarId)groupBy
(bar^.
BarId, bar^.
BarName) return (bar^.
BarId, bar^.
BarName, countRows)
With groupBy you can sort by aggregate functions, like so
(we used let
to restrict the more general countRows
to
SqlSqlExpr (Value Int)
to avoid ambiguity---the second use of
countRows
has its type restricted by the :: Int
below):
r <- select $from
\(foo `InnerJoin
` bar) -> doon
(foo^.
FooBarId==.
bar^.
BarId)groupBy
$ bar^.
BarName let countRows' =countRows
orderBy
[asc
countRows'] return (bar^.
BarName, countRows') forM_ r $ \(Value
name,Value
count) -> do print name print (count :: Int)
Need more columns?
The ToSomeValues
class is defined for SqlExpr
and tuples of SqlExpr
s.
We only have definitions for up to 8 elements in a tuple right now, so it's
possible that you may need to have more than 8 elements.
For example, consider a query with a groupBy
call like this:
groupBy (e0, e1, e2, e3, e4, e5, e6, e7)
This is the biggest you can get with a single tuple. However, you can easily nest the tuples to add more:
groupBy ((e0, e1, e2, e3, e4, e5, e6, e7), e8, e9)
on :: SqlExpr (Value Bool) -> SqlQuery () #
An ON
clause, useful to describe how two tables are related. Cross joins
and tuple-joins do not need an on
clause, but InnerJoin
and the various
outer joins do.
Database.Esqueleto.Experimental in version 4.0.0.0 of the library. The
Experimental
module has a dramatically improved means for introducing
tables and entities that provides more power and less potential for runtime
errors.
If you don't include an on
clause (or include too many!) then a runtime
exception will be thrown.
As an example, consider this simple join:
select
$from
$ \(foo `InnerJoin
` bar) -> doon
(foo^.
FooId==.
bar^.
BarFooId) ...
We need to specify the clause for joining the two columns together. If we had this:
select
$from
$ \(foo `CrossJoin
` bar) -> do ...
Then we can safely omit the on
clause, because the cross join will make
pairs of all records possible.
You can do multiple on
clauses in a query. This query joins three tables,
and has two on
clauses:
select
$from
$ \(foo `InnerJoin
` bar `InnerJoin
` baz) -> doon
(baz^.
BazId==.
bar^.
BarBazId)on
(foo^.
FooId==.
bar^.
BarFooId) ...
Old versions of esqueleto required that you provide the on
clauses in
reverse order. This restriction has been lifted - you can now provide on
clauses in any order, and the SQL should work itself out. The above query is
now totally equivalent to this:
select
$from
$ \(foo `InnerJoin
` bar `InnerJoin
` baz) -> doon
(foo^.
FooId==.
bar^.
BarFooId)on
(baz^.
BazId==.
bar^.
BarBazId) ...
A single value (as opposed to a whole entity). You may use
(
or ^.
)(
to get a ?.
)Value
from an Entity
.
Instances
Applicative Value | |
Functor Value | Since: esqueleto-1.4.4 |
Monad Value | |
(PersistEntity rec, PersistField typ, SymbolToField sym rec typ) => HasField (sym :: Symbol) (SqlExpr (Entity rec)) (SqlExpr (Value typ)) | This instance allows you to use Example: -- persistent model: BlogPost authorId PersonId title Text -- query: This is exactly equivalent to the following: blogPost :: SqlExpr (Entity BlogPost) blogPost ^. BlogPostTitle blogPost ^. #title blogPost.title There's another instance defined on Since: esqueleto-3.5.4.0 |
(PersistEntity rec, PersistField typ, SymbolToField sym rec typ) => HasField (sym :: Symbol) (SqlExpr (Maybe (Entity rec))) (SqlExpr (Value (Maybe typ))) | This instance allows you to use Example: -- persistent model: Person name Text BlogPost title Text authorId PersonId -- query: The following forms are all equivalent: blogPost :: SqlExpr (Maybe (Entity BlogPost)) blogPost ?. BlogPostTitle blogPost ?. #title blogPost.title Since: esqueleto-3.5.4.0 |
(ToFrom a a', SqlSelect b r, ToAlias b, ToAliasReference b, d ~ (a' :& b)) => DoInnerJoin Lateral a (a' -> SqlQuery b, d -> SqlExpr (Value Bool)) d | |
Defined in Database.Esqueleto.Experimental.From.Join | |
(ToFrom a a', ToMaybe b, d ~ (a' :& ToMaybeT b), SqlSelect b r, ToAlias b, ToAliasReference b) => DoLeftJoin Lateral a (a' -> SqlQuery b, d -> SqlExpr (Value Bool)) d | |
Defined in Database.Esqueleto.Experimental.From.Join | |
Show a => Show (Value a) | |
ToAlias (SqlExpr (Value a)) | |
ToAliasReference (SqlExpr (Value a)) | |
ToMaybe (SqlExpr (Value a)) | |
ToSomeValues (SqlExpr (Value a)) | |
Defined in Database.Esqueleto.Internal.Internal toSomeValues :: SqlExpr (Value a) -> [SomeValue] # | |
Eq a => Eq (Value a) | |
Ord a => Ord (Value a) | |
Defined in Database.Esqueleto.Internal.Internal | |
PersistField a => SqlSelect (SqlExpr (Value a)) (Value a) | You may return any single value (i.e. a single column) from
a |
Defined in Database.Esqueleto.Internal.Internal sqlSelectCols :: IdentInfo -> SqlExpr (Value a) -> (Builder, [PersistValue]) # sqlSelectColCount :: Proxy (SqlExpr (Value a)) -> Int # sqlSelectProcessRow :: [PersistValue] -> Either Text (Value a) # sqlInsertInto :: IdentInfo -> SqlExpr (Value a) -> (Builder, [PersistValue]) # | |
type ToMaybeT (SqlExpr (Value a)) | |
A list of single values. There's a limited set of functions
able to work with this data type (such as subList_select
,
valList
, in_
and exists
).
Instances
Show a => Show (ValueList a) | |
Eq a => Eq (ValueList a) | |
Ord a => Ord (ValueList a) | |
Defined in Database.Esqueleto.Internal.Internal |
Data type that represents an INNER JOIN
(see LeftOuterJoin
for an example).
a `InnerJoin` b infixl 2 |
Instances
IsJoinKind InnerJoin | |
Defined in Database.Esqueleto.Internal.Internal | |
FromPreprocess (InnerJoin a b) => From (InnerJoin a b) | |
Defined in Database.Esqueleto.Internal.Internal |
Data type that represents a CROSS JOIN
(see LeftOuterJoin
for an example).
a `CrossJoin` b infixl 2 |
Instances
IsJoinKind CrossJoin | |
Defined in Database.Esqueleto.Internal.Internal | |
FromPreprocess (CrossJoin a b) => From (CrossJoin a b) | |
Defined in Database.Esqueleto.Internal.Internal |
data LeftOuterJoin a b infixl 2 #
Data type that represents a LEFT OUTER JOIN
. For example,
select $from
$ \(person `LeftOuterJoin
` pet) -> ...
is translated into
SELECT ... FROM Person LEFT OUTER JOIN Pet ...
See also: from
.
a `LeftOuterJoin` b infixl 2 |
Instances
IsJoinKind LeftOuterJoin | |
Defined in Database.Esqueleto.Internal.Internal smartJoin :: a -> b -> LeftOuterJoin a b # reifyJoinKind :: LeftOuterJoin a b -> JoinKind # | |
FromPreprocess (LeftOuterJoin a b) => From (LeftOuterJoin a b) | |
Defined in Database.Esqueleto.Internal.Internal from_ :: SqlQuery (LeftOuterJoin a b) # |
data RightOuterJoin a b infixl 2 #
Data type that represents a RIGHT OUTER JOIN
(see LeftOuterJoin
for an example).
a `RightOuterJoin` b infixl 2 |
Instances
IsJoinKind RightOuterJoin | |
Defined in Database.Esqueleto.Internal.Internal smartJoin :: a -> b -> RightOuterJoin a b # reifyJoinKind :: RightOuterJoin a b -> JoinKind # | |
FromPreprocess (RightOuterJoin a b) => From (RightOuterJoin a b) | |
Defined in Database.Esqueleto.Internal.Internal from_ :: SqlQuery (RightOuterJoin a b) # |
data FullOuterJoin a b infixl 2 #
Data type that represents a FULL OUTER JOIN
(see LeftOuterJoin
for an example).
a `FullOuterJoin` b infixl 2 |
Instances
IsJoinKind FullOuterJoin | |
Defined in Database.Esqueleto.Internal.Internal smartJoin :: a -> b -> FullOuterJoin a b # reifyJoinKind :: FullOuterJoin a b -> JoinKind # | |
FromPreprocess (FullOuterJoin a b) => From (FullOuterJoin a b) | |
Defined in Database.Esqueleto.Internal.Internal from_ :: SqlQuery (FullOuterJoin a b) # |
(Internal) A kind of JOIN
.
InnerJoinKind | INNER JOIN |
CrossJoinKind | CROSS JOIN |
LeftOuterJoinKind | LEFT OUTER JOIN |
RightOuterJoinKind | RIGHT OUTER JOIN |
FullOuterJoinKind | FULL OUTER JOIN |
Instances
data OnClauseWithoutMatchingJoinException #
Exception thrown whenever on
is used to create an ON
clause but no matching JOIN
is found.
Instances
data DistinctOn #
Phantom type used by distinctOn
and don
.
data LockingKind #
Different kinds of locking clauses supported by locking
.
Note that each RDBMS has different locking support. The
constructors of this datatype specify only the syntax of the
locking mechanism, not its semantics. For example, even
though both MySQL and PostgreSQL support ForUpdate
, there
are no guarantees that they will behave the same.
Since: esqueleto-2.2.7
ForUpdate |
Since: esqueleto-2.2.7 |
ForUpdateSkipLocked |
Since: esqueleto-2.2.7 |
ForShare |
Since: esqueleto-2.2.7 |
LockInShareMode |
Since: esqueleto-2.2.7 |
class PersistField a => SqlString a #
Phantom class of data types that are treated as strings by the RDBMS. It has no methods because it's only used to avoid type errors such as trying to concatenate integers.
If you have a custom data type or newtype
, feel free to make
it an instance of this class.
Since: esqueleto-2.4.0
Instances
SqlString Html | Since: esqueleto-2.3.0 |
Defined in Database.Esqueleto.Internal.Internal | |
SqlString ByteString | Since: esqueleto-2.3.0 |
Defined in Database.Esqueleto.Internal.Internal | |
SqlString Text | Since: esqueleto-2.3.0 |
Defined in Database.Esqueleto.Internal.Internal | |
SqlString Text | Since: esqueleto-2.3.0 |
Defined in Database.Esqueleto.Internal.Internal | |
SqlString a => SqlString (Maybe a) | Since: esqueleto-2.4.0 |
Defined in Database.Esqueleto.Internal.Internal | |
a ~ Char => SqlString [a] | Since: esqueleto-2.3.0 |
Defined in Database.Esqueleto.Internal.Internal |
Class that enables one to use toBaseId
to convert an entity's
key on a query into another (cf. toBaseId
).
toBaseIdWitness :: Key (BaseEnt ent) -> Key ent #
Convert from the key of the BaseEnt(ity) to the key of the child entity. This function is not actually called, but that it typechecks proves this operation is safe.
Instances
SQL backend for esqueleto
using SqlPersistT
.
Instances
type SqlEntity ent = (PersistEntity ent, PersistEntityBackend ent ~ SqlBackend) #
Constraint synonym for persistent
entities whose backend
is SqlBackend
.
An expression on the SQL backend.
Raw expression: Contains a SqlExprMeta
and a function for
building the expr. It recieves a parameter telling it whether
it is in a parenthesized context, and takes information about the SQL
connection (mainly for escaping names) and returns both an
string (Builder
) and a list of values to be
interpolated by the SQL backend.
Instances
class PersistConfig c where #
Represents a value containing all the configuration options for a specific backend. This abstraction makes it easier to write code that can easily swap backends.
type PersistConfigBackend c :: (Type -> Type) -> Type -> Type #
type PersistConfigPool c #
loadConfig :: Value -> Parser c #
Load the config settings from a Value
, most likely taken from a YAML
config file.
Modify the config settings based on environment variables.
createPoolConfig :: c -> IO (PersistConfigPool c) #
Create a new connection pool based on the given config settings.
runPool :: MonadUnliftIO m => c -> PersistConfigBackend c m a -> PersistConfigPool c -> m a #
Run a database action by taking a connection from the pool.
Instances
(PersistConfig c1, PersistConfig c2, PersistConfigPool c1 ~ PersistConfigPool c2, PersistConfigBackend c1 ~ PersistConfigBackend c2) => PersistConfig (Either c1 c2) | |
Defined in Database.Persist.Class.PersistConfig type PersistConfigBackend (Either c1 c2) :: (Type -> Type) -> Type -> Type # type PersistConfigPool (Either c1 c2) # loadConfig :: Value -> Parser (Either c1 c2) # applyEnv :: Either c1 c2 -> IO (Either c1 c2) # createPoolConfig :: Either c1 c2 -> IO (PersistConfigPool (Either c1 c2)) # runPool :: MonadUnliftIO m => Either c1 c2 -> PersistConfigBackend (Either c1 c2) m a -> PersistConfigPool (Either c1 c2) -> m a # |
type family PersistConfigBackend c :: (Type -> Type) -> Type -> Type #
Instances
type PersistConfigBackend (Either c1 c2) | |
Defined in Database.Persist.Class.PersistConfig |
type family PersistConfigPool c #
Instances
type PersistConfigPool (Either c1 c2) | |
Defined in Database.Persist.Class.PersistConfig |
newtype ConstraintNameHS #
An ConstraintNameHS
represents the Haskell-side name that persistent
will use for a constraint.
Since: persistent-2.12.0.0
Instances
newtype ConstraintNameDB #
A ConstraintNameDB
represents the datastore-side name that persistent
will use for a constraint.
Since: persistent-2.12.0.0
Instances
newtype EntityNameDB #
An EntityNameDB
represents the datastore-side name that persistent
will use for an entity.
Since: persistent-2.12.0.0
Instances
newtype EntityNameHS #
An EntityNameHS
represents the Haskell-side name that persistent
will use for an entity.
Since: persistent-2.12.0.0
Instances
newtype FieldNameHS #
A FieldNameHS
represents the Haskell-side name that persistent
will use for a field.
Since: persistent-2.12.0.0
Instances
newtype FieldNameDB #
An EntityNameDB
represents the datastore-side name that persistent
will use for an entity.
Since: persistent-2.12.0.0
Instances
class DatabaseName a where #
Convenience operations for working with '-NameDB' types.
Since: persistent-2.12.0.0
escapeWith :: (Text -> str) -> a -> str #
Instances
DatabaseName ConstraintNameDB | Since: persistent-2.12.0.0 |
Defined in Database.Persist.Names escapeWith :: (Text -> str) -> ConstraintNameDB -> str # | |
DatabaseName EntityNameDB | |
Defined in Database.Persist.Names escapeWith :: (Text -> str) -> EntityNameDB -> str # | |
DatabaseName FieldNameDB | Since: persistent-2.12.0.0 |
Defined in Database.Persist.Names escapeWith :: (Text -> str) -> FieldNameDB -> str # |
data LiteralType #
A type that determines how a backend should handle the literal.
Since: persistent-2.12.0.0
Escaped | The accompanying value will be escaped before inserting into the database. This is the correct default choice to use. Since: persistent-2.12.0.0 |
Unescaped | The accompanying value will not be escaped when inserting into the database. This is potentially dangerous - use this with care. Since: persistent-2.12.0.0 |
DbSpecific | The Since: persistent-2.12.0.0 |
Instances
Read LiteralType | |
Defined in Database.Persist.PersistValue readsPrec :: Int -> ReadS LiteralType # readList :: ReadS [LiteralType] # readPrec :: ReadPrec LiteralType # readListPrec :: ReadPrec [LiteralType] # | |
Show LiteralType | |
Defined in Database.Persist.PersistValue showsPrec :: Int -> LiteralType -> ShowS # show :: LiteralType -> String # showList :: [LiteralType] -> ShowS # | |
Eq LiteralType | |
Defined in Database.Persist.PersistValue (==) :: LiteralType -> LiteralType -> Bool # (/=) :: LiteralType -> LiteralType -> Bool # | |
Ord LiteralType | |
Defined in Database.Persist.PersistValue compare :: LiteralType -> LiteralType -> Ordering # (<) :: LiteralType -> LiteralType -> Bool # (<=) :: LiteralType -> LiteralType -> Bool # (>) :: LiteralType -> LiteralType -> Bool # (>=) :: LiteralType -> LiteralType -> Bool # max :: LiteralType -> LiteralType -> LiteralType # min :: LiteralType -> LiteralType -> LiteralType # |
data PersistValue #
A raw value which can be stored in any backend and can be marshalled to
and from a PersistField
.
PersistText Text | |
PersistByteString ByteString | |
PersistInt64 Int64 | |
PersistDouble Double | |
PersistRational Rational | |
PersistBool Bool | |
PersistDay Day | |
PersistTimeOfDay TimeOfDay | |
PersistUTCTime UTCTime | |
PersistNull | |
PersistList [PersistValue] | |
PersistMap [(Text, PersistValue)] | |
PersistObjectId ByteString | Intended especially for MongoDB backend |
PersistArray [PersistValue] | Intended especially for PostgreSQL backend for text arrays |
PersistLiteral_ LiteralType ByteString | This constructor is used to specify some raw literal value for the
backend. The Since: persistent-2.12.0.0 |
pattern PersistLiteral :: ByteString -> PersistValue | This pattern synonym used to be a data constructor on Since: persistent-2.12.0.0 |
pattern PersistDbSpecific :: ByteString -> PersistValue | This pattern synonym used to be a data constructor for the
If you use this, it will overlap a patern match on the 'PersistLiteral_,
Since: persistent-2.12.0.0 |
pattern PersistLiteralEscaped :: ByteString -> PersistValue | This pattern synonym used to be a data constructor on Since: persistent-2.12.0.0 |
Instances
data IsolationLevel #
Please refer to the documentation for the database in question for a full overview of the semantics of the varying isloation levels
Instances
A FieldDef
represents the inormation that persistent
knows about
a field of a datatype. This includes information used to parse the field
out of the database and what the field corresponds to.
FieldDef | |
|
data PersistUpdate #
Instances
Read PersistUpdate | |
Defined in Database.Persist.Types.Base readsPrec :: Int -> ReadS PersistUpdate # readList :: ReadS [PersistUpdate] # | |
Show PersistUpdate | |
Defined in Database.Persist.Types.Base showsPrec :: Int -> PersistUpdate -> ShowS # show :: PersistUpdate -> String # showList :: [PersistUpdate] -> ShowS # | |
Lift PersistUpdate | |
Defined in Database.Persist.Types.Base lift :: Quote m => PersistUpdate -> m Exp # liftTyped :: forall (m :: Type -> Type). Quote m => PersistUpdate -> Code m PersistUpdate # |
data UpdateException #
Instances
Exception UpdateException | |
Defined in Database.Persist.Types.Base | |
Show UpdateException | |
Defined in Database.Persist.Types.Base showsPrec :: Int -> UpdateException -> ShowS # show :: UpdateException -> String # showList :: [UpdateException] -> ShowS # |
data PersistFilter #
Instances
Read PersistFilter | |
Defined in Database.Persist.Types.Base readsPrec :: Int -> ReadS PersistFilter # readList :: ReadS [PersistFilter] # | |
Show PersistFilter | |
Defined in Database.Persist.Types.Base showsPrec :: Int -> PersistFilter -> ShowS # show :: PersistFilter -> String # showList :: [PersistFilter] -> ShowS # | |
Lift PersistFilter | |
Defined in Database.Persist.Types.Base lift :: Quote m => PersistFilter -> m Exp # liftTyped :: forall (m :: Type -> Type). Quote m => PersistFilter -> Code m PersistFilter # |
A SQL data type. Naming attempts to reflect the underlying Haskell datatypes, eg SqlString instead of SqlVarchar. Different SQL databases may have different translations for these types.
SqlString | |
SqlInt32 | |
SqlInt64 | |
SqlReal | |
SqlNumeric Word32 Word32 | |
SqlBool | |
SqlDay | |
SqlTime | |
SqlDayTime | Always uses UTC timezone |
SqlBlob | |
SqlOther Text | a backend-specific name |
data PersistException #
PersistError Text | Generic Exception |
PersistMarshalError Text | |
PersistInvalidField Text | |
PersistForeignConstraintUnmet Text | |
PersistMongoDBError Text | |
PersistMongoDBUnsupported Text |
Instances
Exception PersistException | |
Defined in Database.Persist.Types.Base | |
Show PersistException | |
Defined in Database.Persist.Types.Base showsPrec :: Int -> PersistException -> ShowS # show :: PersistException -> String # showList :: [PersistException] -> ShowS # |
data CascadeAction #
An action that might happen on a deletion or update on a foreign key change.
Since: persistent-2.11.0
Instances
data FieldCascade #
This datatype describes how a foreign reference field cascades deletes or updates.
This type is used in both parsing the model definitions and performing
migrations. A Nothing
in either of the field values means that the
user has not specified a CascadeAction
. An unspecified CascadeAction
is defaulted to Restrict
when doing migrations.
Since: persistent-2.11.0
FieldCascade | |
|
Instances
data ForeignDef #
ForeignDef | |
|
Instances
type ForeignFieldDef = (FieldNameHS, FieldNameDB) #
Used instead of FieldDef to generate a smaller amount of code
data CompositeDef #
CompositeDef | |
|
Instances
Type for storing the Uniqueness constraint in the Schema. Assume you have the following schema with a uniqueness constraint:
Person name String age Int UniqueAge age
This will be represented as:
UniqueDef { uniqueHaskell = ConstraintNameHS (packPTH UniqueAge) , uniqueDBName = ConstraintNameDB (packPTH "unique_age") , uniqueFields = [(FieldNameHS (packPTH "age"), FieldNameDB (packPTH "age"))] , uniqueAttrs = [] }
UniqueDef | |
|
data EmbedFieldDef #
An EmbedFieldDef is the same as a FieldDef But it is only used for embeddedFields so it only has data needed for embedding
EmbedFieldDef | |
|
Instances
data EmbedEntityDef #
An EmbedEntityDef is the same as an EntityDef But it is only used for fieldReference so it only has data needed for embedding
Instances
data ReferenceDef #
There are 3 kinds of references 1) composite (to fields that exist in the record) 2) single field 3) embedded
NoReference | |
ForeignRef !EntityNameHS | A ForeignRef has a late binding to the EntityDef it references via name and has the Haskell type of the foreign key in the form of FieldType |
EmbedRef EntityNameHS | |
CompositeRef CompositeDef | |
SelfReference | A SelfReference stops an immediate cycle which causes non-termination at compile-time (issue #311). |
Instances
A FieldType
describes a field parsed from the QuasiQuoter and is
used to determine the Haskell type in the generated code.
name Text
parses into FTTypeCon Nothing Text
name T.Text
parses into FTTypeCon (Just T Text)
name (Jsonb User)
parses into:
FTApp (FTTypeCon Nothing Jsonb) (FTTypeCon Nothing User)
FTTypeCon (Maybe Text) Text | Optional module and name. |
FTTypePromoted Text | |
FTApp FieldType FieldType | |
FTList FieldType |
Attributes that may be attached to fields that can affect migrations and serialization in backend-specific ways.
While we endeavor to, we can't forsee all use cases for all backends,
and so FieldAttr
is extensible through its constructor FieldAttrOther
.
Since: persistent-2.11.0.0
FieldAttrMaybe | The Example: User name Text Maybe |
FieldAttrNullable | This indicates that the column is nullable, but should not have
a data What = NoWhat | Hello Text instance PersistField What where fromPersistValue PersistNull = pure NoWhat fromPersistValue pv = Hello $ fromPersistValue pv instance PersistFieldSql What where sqlType _ = SqlString User what What nullable |
FieldAttrMigrationOnly | This tag means that the column will not be present on the Haskell code, but will not be removed from the database. Useful to deprecate fields in phases. You should set the column to be nullable in the database. Otherwise, inserts won't have values. User oldName Text MigrationOnly newName Text |
FieldAttrSafeToRemove | A Useful after you've used User oldName Text SafeToRemove newName Text |
FieldAttrNoreference | This attribute indicates that we should create a foreign key reference
from a column. By default, This is useful if you want to use the explicit foreign key syntax. Post title Text Comment postId PostId noreference Foreign Post fk_comment_post postId |
FieldAttrReference Text | This is set to specify precisely the database table the column refers to. Post title Text Comment postId PostId references="post" You should not need this - |
FieldAttrConstraint Text | Specify a name for the constraint on the foreign key reference for this table. Post title Text Comment postId PostId constraint="my_cool_constraint_name" |
FieldAttrDefault Text | Specify the default value for a column. User createdAt UTCTime default="NOW()" Note that a |
FieldAttrSqltype Text | Specify a custom SQL type for the column. Generally, you should define
a custom datatype with a custom User uuid Text sqltype=UUID |
FieldAttrMaxlen Integer | Set a maximum length for a column. Useful for VARCHAR and indexes. User name Text maxlen=200 UniqueName name |
FieldAttrSql Text | Specify the database name of the column. User blarghle Int sql="b_l_a_r_g_h_l_e" Useful for performing phased migrations, where one column is renamed to another column over time. |
FieldAttrOther Text | A grab bag of random attributes that were unrecognized by the parser. |
data EntityIdDef #
The definition for the entity's primary key ID.
Since: persistent-2.13.0.0
EntityIdField !FieldDef | The entity has a single key column, and it is a surrogate key - that
is, you can't go from Since: persistent-2.13.0.0 |
EntityIdNaturalKey !CompositeDef | The entity has a natural key. This means you can write A natural key can have one or more columns. Since: persistent-2.13.0.0 |
Instances
An EntityDef
represents the information that persistent
knows
about an Entity. It uses this information to generate the Haskell
datatype, the SQL migrations, and other relevant conversions.
data WhyNullable #
The reason why a field is nullable
is very important. A
field that is nullable because of a Maybe
tag will have its
type changed from A
to Maybe A
. OTOH, a field that is
nullable because of a nullable
tag will remain with the same
type.
Instances
Show WhyNullable | |
Defined in Database.Persist.Types.Base showsPrec :: Int -> WhyNullable -> ShowS # show :: WhyNullable -> String # showList :: [WhyNullable] -> ShowS # | |
Eq WhyNullable | |
Defined in Database.Persist.Types.Base (==) :: WhyNullable -> WhyNullable -> Bool # (/=) :: WhyNullable -> WhyNullable -> Bool # |
data IsNullable #
Instances
Show IsNullable | |
Defined in Database.Persist.Types.Base showsPrec :: Int -> IsNullable -> ShowS # show :: IsNullable -> String # showList :: [IsNullable] -> ShowS # | |
Eq IsNullable | |
Defined in Database.Persist.Types.Base (==) :: IsNullable -> IsNullable -> Bool # (/=) :: IsNullable -> IsNullable -> Bool # |
A Checkmark
should be used as a field type whenever a
uniqueness constraint should guarantee that a certain kind of
record may appear at most once, but other kinds of records may
appear any number of times.
NOTE: You need to mark any Checkmark
fields as nullable
(see the following example).
For example, suppose there's a Location
entity that
represents where a user has lived:
Location user UserId name Text current Checkmark nullable UniqueLocation user current
The UniqueLocation
constraint allows any number of
Inactive
Location
s to be current
. However, there may be
at most one current
Location
per user (i.e., either zero
or one per user).
This data type works because of the way that SQL treats
NULL
able fields within uniqueness constraints. The SQL
standard says that NULL
values should be considered
different, so we represent Inactive
as SQL NULL
, thus
allowing any number of Inactive
records. On the other hand,
we represent Active
as TRUE
, so the uniqueness constraint
will disallow more than one Active
record.
Note: There may be DBMSs that do not respect the SQL
standard's treatment of NULL
values on uniqueness
constraints, please check if this data type works before
relying on it.
The SQL BOOLEAN
type is used because it's the smallest data
type available. Note that we never use FALSE
, just TRUE
and NULL
. Provides the same behavior Maybe ()
would if
()
was a valid PersistField
.
Active | When used on a uniqueness constraint, there
may be at most one |
Inactive | When used on a uniqueness constraint, there
may be any number of |
Instances
Bounded Checkmark | |
Enum Checkmark | |
Defined in Database.Persist.Types.Base succ :: Checkmark -> Checkmark # pred :: Checkmark -> Checkmark # fromEnum :: Checkmark -> Int # enumFrom :: Checkmark -> [Checkmark] # enumFromThen :: Checkmark -> Checkmark -> [Checkmark] # enumFromTo :: Checkmark -> Checkmark -> [Checkmark] # enumFromThenTo :: Checkmark -> Checkmark -> Checkmark -> [Checkmark] # | |
Read Checkmark | |
Show Checkmark | |
Defined in Database.Persist.Types.Base |