-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/
-- | Type-safe, multi-backend data serialization.
--
-- Hackage documentation generation is not reliable. For up to date
-- documentation, please see:
-- http://www.stackage.org/package/persistent.
@package persistent
@version 2.2.3
module Database.Persist.Types
-- | 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 Locations 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
-- NULLable 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.
data Checkmark
-- | When used on a uniqueness constraint, there may be at most one
-- Active record.
Active :: Checkmark
-- | When used on a uniqueness constraint, there may be any number of
-- Inactive records.
Inactive :: Checkmark
data IsNullable
Nullable :: !WhyNullable -> IsNullable
NotNullable :: IsNullable
-- | 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.
data WhyNullable
ByMaybeAttr :: WhyNullable
ByNullableAttr :: WhyNullable
data EntityDef
EntityDef :: !HaskellName -> !DBName -> !FieldDef -> ![Attr] -> ![FieldDef] -> ![UniqueDef] -> ![ForeignDef] -> ![Text] -> !(Map Text [ExtraLine]) -> !Bool -> EntityDef
[entityHaskell] :: EntityDef -> !HaskellName
[entityDB] :: EntityDef -> !DBName
[entityId] :: EntityDef -> !FieldDef
[entityAttrs] :: EntityDef -> ![Attr]
[entityFields] :: EntityDef -> ![FieldDef]
[entityUniques] :: EntityDef -> ![UniqueDef]
[entityForeigns] :: EntityDef -> ![ForeignDef]
[entityDerives] :: EntityDef -> ![Text]
[entityExtra] :: EntityDef -> !(Map Text [ExtraLine])
[entitySum] :: EntityDef -> !Bool
entityPrimary :: EntityDef -> Maybe CompositeDef
entityKeyFields :: EntityDef -> [FieldDef]
keyAndEntityFields :: EntityDef -> [FieldDef]
type ExtraLine = [Text]
newtype HaskellName
HaskellName :: Text -> HaskellName
[unHaskellName] :: HaskellName -> Text
newtype DBName
DBName :: Text -> DBName
[unDBName] :: DBName -> Text
type Attr = Text
data FieldType
-- | Optional module and name.
FTTypeCon :: (Maybe Text) -> Text -> FieldType
FTApp :: FieldType -> FieldType -> FieldType
FTList :: FieldType -> FieldType
data FieldDef
FieldDef :: !HaskellName -> !DBName -> !FieldType -> !SqlType -> ![Attr] -> !Bool -> !ReferenceDef -> FieldDef
-- | name of the field
[fieldHaskell] :: FieldDef -> !HaskellName
[fieldDB] :: FieldDef -> !DBName
[fieldType] :: FieldDef -> !FieldType
[fieldSqlType] :: FieldDef -> !SqlType
-- | user annotations for a field
[fieldAttrs] :: FieldDef -> ![Attr]
-- | a strict field in the data type. Default: true
[fieldStrict] :: FieldDef -> !Bool
[fieldReference] :: FieldDef -> !ReferenceDef
-- | There are 3 kinds of references 1) composite (to fields that exist in
-- the record) 2) single field 3) embedded
data ReferenceDef
NoReference :: ReferenceDef
-- | A ForeignRef has a late binding to the EntityDef it references via
-- HaskellName and has the Haskell type of the foreign key in the form of
-- FieldType
ForeignRef :: !HaskellName -> !FieldType -> ReferenceDef
EmbedRef :: EmbedEntityDef -> ReferenceDef
CompositeRef :: CompositeDef -> ReferenceDef
-- | A SelfReference stops an immediate cycle which causes non-termination
-- at compile-time (issue #311).
SelfReference :: ReferenceDef
-- | An EmbedEntityDef is the same as an EntityDef But it is only used for
-- fieldReference so it only has data needed for embedding
data EmbedEntityDef
EmbedEntityDef :: !HaskellName -> ![EmbedFieldDef] -> EmbedEntityDef
[embeddedHaskell] :: EmbedEntityDef -> !HaskellName
[embeddedFields] :: EmbedEntityDef -> ![EmbedFieldDef]
-- | An EmbedFieldDef is the same as a FieldDef But it is only used for
-- embeddedFields so it only has data needed for embedding
data EmbedFieldDef
EmbedFieldDef :: !DBName -> Maybe EmbedEntityDef -> Maybe HaskellName -> EmbedFieldDef
[emFieldDB] :: EmbedFieldDef -> !DBName
[emFieldEmbed] :: EmbedFieldDef -> Maybe EmbedEntityDef
-- | emFieldEmbed can create a cycle (issue #311) when a cycle is
-- detected, emFieldEmbed will be Nothing and emFieldCycle
-- will be Just
[emFieldCycle] :: EmbedFieldDef -> Maybe HaskellName
toEmbedEntityDef :: EntityDef -> EmbedEntityDef
data UniqueDef
UniqueDef :: !HaskellName -> !DBName -> ![(HaskellName, DBName)] -> ![Attr] -> UniqueDef
[uniqueHaskell] :: UniqueDef -> !HaskellName
[uniqueDBName] :: UniqueDef -> !DBName
[uniqueFields] :: UniqueDef -> ![(HaskellName, DBName)]
[uniqueAttrs] :: UniqueDef -> ![Attr]
data CompositeDef
CompositeDef :: ![FieldDef] -> ![Attr] -> CompositeDef
[compositeFields] :: CompositeDef -> ![FieldDef]
[compositeAttrs] :: CompositeDef -> ![Attr]
-- | Used instead of FieldDef to generate a smaller amount of code
type ForeignFieldDef = (HaskellName, DBName)
data ForeignDef
ForeignDef :: !HaskellName -> !DBName -> !HaskellName -> !DBName -> ![(ForeignFieldDef, ForeignFieldDef)] -> ![Attr] -> Bool -> ForeignDef
[foreignRefTableHaskell] :: ForeignDef -> !HaskellName
[foreignRefTableDBName] :: ForeignDef -> !DBName
[foreignConstraintNameHaskell] :: ForeignDef -> !HaskellName
[foreignConstraintNameDBName] :: ForeignDef -> !DBName
[foreignFields] :: ForeignDef -> ![(ForeignFieldDef, ForeignFieldDef)]
[foreignAttrs] :: ForeignDef -> ![Attr]
[foreignNullable] :: ForeignDef -> Bool
data PersistException
-- | Generic Exception
PersistError :: Text -> PersistException
PersistMarshalError :: Text -> PersistException
PersistInvalidField :: Text -> PersistException
PersistForeignConstraintUnmet :: Text -> PersistException
PersistMongoDBError :: Text -> PersistException
PersistMongoDBUnsupported :: Text -> PersistException
-- | A raw value which can be stored in any backend and can be marshalled
-- to and from a PersistField.
data PersistValue
PersistText :: Text -> PersistValue
PersistByteString :: ByteString -> PersistValue
PersistInt64 :: Int64 -> PersistValue
PersistDouble :: Double -> PersistValue
PersistRational :: Rational -> PersistValue
PersistBool :: Bool -> PersistValue
PersistDay :: Day -> PersistValue
PersistTimeOfDay :: TimeOfDay -> PersistValue
PersistUTCTime :: UTCTime -> PersistValue
PersistNull :: PersistValue
PersistList :: [PersistValue] -> PersistValue
PersistMap :: [(Text, PersistValue)] -> PersistValue
-- | Intended especially for MongoDB backend
PersistObjectId :: ByteString -> PersistValue
-- | Using PersistDbSpecific allows you to use types specific to a
-- particular backend For example, below is a simple example of the
-- PostGIS geography type:
--
--
-- data Geo = Geo ByteString
--
-- instance PersistField Geo where
-- toPersistValue (Geo t) = PersistDbSpecific t
--
-- fromPersistValue (PersistDbSpecific t) = Right $ Geo $ Data.ByteString.concat ["'", t, "'"]
-- fromPersistValue _ = Left "Geo values must be converted from PersistDbSpecific"
--
-- instance PersistFieldSql Geo where
-- sqlType _ = SqlOther "GEOGRAPHY(POINT,4326)"
--
-- toPoint :: Double -> Double -> Geo
-- toPoint lat lon = Geo $ Data.ByteString.concat ["'POINT(", ps $ lon, " ", ps $ lat, ")'"]
-- where ps = Data.Text.pack . show
--
--
-- If Foo has a geography field, we can then perform insertions like the
-- following:
--
--
-- insert $ Foo (toPoint 44 44)
--
PersistDbSpecific :: ByteString -> PersistValue
fromPersistValueText :: PersistValue -> Either Text Text
-- | 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.
data SqlType
SqlString :: SqlType
SqlInt32 :: SqlType
SqlInt64 :: SqlType
SqlReal :: SqlType
SqlNumeric :: Word32 -> Word32 -> SqlType
SqlBool :: SqlType
SqlDay :: SqlType
SqlTime :: SqlType
-- | Always uses UTC timezone
SqlDayTime :: SqlType
SqlBlob :: SqlType
-- | a backend-specific name
SqlOther :: Text -> SqlType
data PersistFilter
Eq :: PersistFilter
Ne :: PersistFilter
Gt :: PersistFilter
Lt :: PersistFilter
Ge :: PersistFilter
Le :: PersistFilter
In :: PersistFilter
NotIn :: PersistFilter
BackendSpecificFilter :: Text -> PersistFilter
data UpdateException
KeyNotFound :: String -> UpdateException
UpsertError :: String -> UpdateException
data OnlyUniqueException
OnlyUniqueException :: String -> OnlyUniqueException
data PersistUpdate
Assign :: PersistUpdate
Add :: PersistUpdate
Subtract :: PersistUpdate
Multiply :: PersistUpdate
Divide :: PersistUpdate
BackendSpecificUpdate :: Text -> PersistUpdate
data SomePersistField
SomePersistField :: a -> SomePersistField
-- | Updating a database entity
--
-- Persistent users use combinators to create these
data Update record
Update :: EntityField record typ -> typ -> PersistUpdate -> Update record
[updateField] :: Update record -> EntityField record typ
[updateValue] :: Update record -> typ
[updateUpdate] :: Update record -> PersistUpdate
BackendUpdate :: (BackendSpecificUpdate (PersistEntityBackend record) record) -> Update record
-- | query options
--
-- Persistent users use these directly
data SelectOpt record
Asc :: (EntityField record typ) -> SelectOpt record
Desc :: (EntityField record typ) -> SelectOpt record
OffsetBy :: Int -> SelectOpt record
LimitTo :: Int -> SelectOpt record
-- | Filters which are available for select, updateWhere
-- and deleteWhere. Each filter constructor specifies the field
-- being filtered on, the type of comparison applied (equals, not equals,
-- etc) and the argument for the comparison.
--
-- Persistent users use combinators to create these
data Filter record
Filter :: EntityField record typ -> Either typ [typ] -> PersistFilter -> Filter record
[filterField] :: Filter record -> EntityField record typ
[filterValue] :: Filter record -> Either typ [typ]
[filterFilter] :: Filter record -> PersistFilter
-- | convenient for internal use, not needed for the API
FilterAnd :: [Filter record] -> Filter record
FilterOr :: [Filter record] -> Filter record
BackendFilter :: (BackendSpecificFilter (PersistEntityBackend record) record) -> Filter record
-- | Datatype that represents an entity, with both its Key and its
-- Haskell record representation.
--
-- When using a SQL-based backend (such as SQLite or PostgreSQL), an
-- Entity may take any number of columns depending on how many
-- fields it has. In order to reconstruct your entity on the Haskell
-- side, persistent needs all of your entity columns and in the
-- right order. Note that you don't need to worry about this when using
-- persistent's API since everything is handled correctly behind
-- the scenes.
--
-- However, if you want to issue a raw SQL command that returns an
-- Entity, then you have to be careful with the column order.
-- While you could use SELECT Entity.* WHERE ... and that would
-- work most of the time, there are times when the order of the columns
-- on your database is different from the order that persistent
-- expects (for example, if you add a new field in the middle of you
-- entity definition and then use the migration code --
-- persistent will expect the column to be in the middle, but
-- your DBMS will put it as the last column). So, instead of using a
-- query like the one above, you may use rawSql (from the
-- Database.Persist.GenericSql module) with its /entity selection
-- placeholder/ (a double question mark ??). Using
-- rawSql the query above must be written as SELECT ?? WHERE
-- ... Then rawSql will replace ?? with the list
-- of all columns that we need from your entity in the right order. If
-- your query returns two entities (i.e. (Entity backend a, Entity
-- backend b)), then you must you use SELECT ??, ?? WHERE
-- ..., and so on.
data Entity record
Entity :: Key record -> record -> Entity record
[entityKey] :: Entity record -> Key record
[entityVal] :: Entity record -> record
module Database.Persist.Quasi
-- | Parses a quasi-quoted syntax into a list of entity definitions.
parse :: PersistSettings -> Text -> [EntityDef]
data PersistSettings
PersistSettings :: !(Text -> Text) -> !Bool -> !Text -> PersistSettings
[psToDBName] :: PersistSettings -> !(Text -> Text)
-- | Whether fields are by default strict. Default value: True.
--
-- Since 1.2
[psStrictFields] :: PersistSettings -> !Bool
-- | The name of the id column. Default value: id The name of the
-- id column can also be changed on a per-model basis
-- https://github.com/yesodweb/persistent/wiki/Persistent-entity-syntax
--
-- Since 2.0
[psIdName] :: PersistSettings -> !Text
upperCaseSettings :: PersistSettings
lowerCaseSettings :: PersistSettings
nullable :: [Text] -> IsNullable
instance GHC.Classes.Eq Database.Persist.Quasi.Token
instance GHC.Show.Show Database.Persist.Quasi.Token
instance GHC.Show.Show a => GHC.Show.Show (Database.Persist.Quasi.ParseState a)
module Database.Persist.Class
-- | ToBackendKey converts a PersistEntity Key into a
-- BackendKey This can be used by each backend to convert between
-- a Key and a plain Haskell type. For Sql, that is done with
-- toSqlKey and fromSqlKey.
--
-- By default, a PersistEntity uses the default BackendKey
-- for its Key and is an instance of ToBackendKey
--
-- A Key that instead uses a custom type will not be an instance
-- of ToBackendKey
class (PersistEntity record, PersistEntityBackend record ~ backend, PersistStore backend) => ToBackendKey backend record
toBackendKey :: ToBackendKey backend record => Key record -> BackendKey backend
fromBackendKey :: ToBackendKey backend record => BackendKey backend -> Key record
class (Show (BackendKey backend), Read (BackendKey backend), Eq (BackendKey backend), Ord (BackendKey backend), PersistField (BackendKey backend), ToJSON (BackendKey backend), FromJSON (BackendKey backend)) => PersistStore backend where data BackendKey backend insert_ val = insert val >> return () insertMany = mapM insert insertMany_ x = insertMany x >> return () insertEntityMany = mapM_ (\ (Entity k record) -> insertKey k record) updateGet key ups = do { update key ups; get key >>= maybe (liftIO $ throwIO $ KeyNotFound $ show key) return } where {
data family BackendKey backend;
}
-- | Get a record by identifier, if available.
get :: (PersistStore backend, MonadIO m, backend ~ PersistEntityBackend val, PersistEntity val) => Key val -> ReaderT backend m (Maybe val)
-- | Create a new record in the database, returning an automatically
-- created key (in SQL an auto-increment id).
insert :: (PersistStore backend, MonadIO m, backend ~ PersistEntityBackend val, PersistEntity val) => val -> ReaderT backend m (Key val)
-- | Same as insert, but doesn't return a Key.
insert_ :: (PersistStore backend, MonadIO m, backend ~ PersistEntityBackend val, PersistEntity val) => val -> ReaderT backend m ()
-- | Create multiple records in the database and return their Keys.
--
-- If you don't need the inserted Keys, use insertMany_.
--
-- The MongoDB and PostgreSQL backends insert all records and retrieve
-- their keys in one database query.
--
-- The SQLite and MySQL backends use the slow, default implementation of
-- mapM insert.
insertMany :: (PersistStore backend, MonadIO m, backend ~ PersistEntityBackend val, PersistEntity val) => [val] -> ReaderT backend m [Key val]
-- | Same as insertMany, but doesn't return any Keys.
--
-- The MongoDB, PostgreSQL, SQLite and MySQL backends insert all records
-- in one database query.
insertMany_ :: (PersistStore backend, MonadIO m, backend ~ PersistEntityBackend val, PersistEntity val) => [val] -> ReaderT backend m ()
-- | Same as insertMany_, but takes an Entity instead of just
-- a record.
--
-- Useful when migrating data from one entity to another and want to
-- preserve ids.
--
-- The MongoDB backend inserts all the entities in one database query.
--
-- The SQL backends use the slow, default implementation of mapM_
-- insertKey.
insertEntityMany :: (PersistStore backend, MonadIO m, backend ~ PersistEntityBackend val, PersistEntity val) => [Entity val] -> ReaderT backend m ()
-- | Create a new record in the database using the given key.
insertKey :: (PersistStore backend, MonadIO m, backend ~ PersistEntityBackend val, PersistEntity val) => Key val -> val -> ReaderT backend m ()
-- | Put the record in the database with the given key. Unlike
-- replace, if a record with the given key does not exist then a
-- new record will be inserted.
repsert :: (PersistStore backend, MonadIO m, backend ~ PersistEntityBackend val, PersistEntity val) => Key val -> val -> ReaderT backend m ()
-- | Replace the record in the database with the given key. Note that the
-- result is undefined if such record does not exist, so you must use
-- 'insertKey or repsert in these cases.
replace :: (PersistStore backend, MonadIO m, backend ~ PersistEntityBackend val, PersistEntity val) => Key val -> val -> ReaderT backend m ()
-- | Delete a specific record by identifier. Does nothing if record does
-- not exist.
delete :: (PersistStore backend, MonadIO m, backend ~ PersistEntityBackend val, PersistEntity val) => Key val -> ReaderT backend m ()
-- | Update individual fields on a specific record.
update :: (PersistStore backend, MonadIO m, PersistEntity val, backend ~ PersistEntityBackend val) => Key val -> [Update val] -> ReaderT backend m ()
-- | Update individual fields on a specific record, and retrieve the
-- updated value from the database.
--
-- Note that this function will throw an exception if the given key is
-- not found in the database.
updateGet :: (PersistStore backend, MonadIO m, PersistEntity val, backend ~ PersistEntityBackend val) => Key val -> [Update val] -> ReaderT backend m val
-- | Same as get, but for a non-null (not Maybe) foreign key Unsafe unless
-- your database is enforcing that the foreign key is valid
getJust :: (PersistStore backend, PersistEntity val, Show (Key val), backend ~ PersistEntityBackend val, MonadIO m) => Key val -> ReaderT backend m val
-- | curry this to make a convenience function that loads an associated
-- model
--
--
-- foreign = belongsTo foerignId
--
belongsTo :: (PersistStore backend, PersistEntity ent1, PersistEntity ent2, backend ~ PersistEntityBackend ent2, MonadIO m) => (ent1 -> Maybe (Key ent2)) -> ent1 -> ReaderT backend m (Maybe ent2)
-- | same as belongsTo, but uses getJust and therefore is
-- similarly unsafe
belongsToJust :: (PersistStore backend, PersistEntity ent1, PersistEntity ent2, backend ~ PersistEntityBackend ent2, MonadIO m) => (ent1 -> Key ent2) -> ent1 -> ReaderT backend m ent2
-- | like insert, but returns the complete Entity
insertEntity :: (PersistStore backend, PersistEntity e, backend ~ PersistEntityBackend e, MonadIO m) => e -> ReaderT backend m (Entity e)
-- | Queries against Unique keys (other than the id Key).
--
-- Please read the general Persistent documentation to learn how to
-- create Unique keys.
--
-- Using this with an Entity without a Unique key leads to undefined
-- behavior. A few of these functions require a *single* Unique,
-- so using an Entity with multiple Uniques is also undefined. In
-- these cases persistent's goal is to throw an exception as soon as
-- possible, but persistent is still transitioning to that.
--
-- SQL backends automatically create uniqueness constraints, but for
-- MongoDB you must manually place a unique index on a field to have a
-- uniqueness constraint.
--
-- Some functions in this module (insertUnique, insertBy, and
-- replaceUnique) first query the unique indexes to check for conflicts.
-- You could instead optimistically attempt to perform the operation
-- (e.g. replace instead of replaceUnique). However,
--
--
-- - there is some fragility to trying to catch the correct exception
-- and determing the column of failure.
-- - an exception will automatically abort the current SQL
-- transaction
--
class PersistStore backend => PersistUnique backend where insertUnique datum = do { conflict <- checkUnique datum; case conflict of { Nothing -> Just `liftM` insert datum Just _ -> return Nothing } } upsert record updates = do { uniqueKey <- onlyUnique record; mExists <- getBy uniqueKey; k <- case mExists of { Just (Entity k _) -> do { when (null updates) (replace k record); return k } Nothing -> insert record }; Entity k `liftM` updateGet k updates }
-- | Get a record by unique key, if available. Returns also the identifier.
getBy :: (PersistUnique backend, MonadIO m, backend ~ PersistEntityBackend val, PersistEntity val) => Unique val -> ReaderT backend m (Maybe (Entity val))
-- | Delete a specific record by unique key. Does nothing if no record
-- matches.
deleteBy :: (PersistUnique backend, MonadIO m, PersistEntityBackend val ~ backend, PersistEntity val) => Unique val -> ReaderT backend m ()
-- | Like insert, but returns Nothing when the record
-- couldn't be inserted because of a uniqueness constraint.
insertUnique :: (PersistUnique backend, MonadIO m, PersistEntityBackend val ~ backend, PersistEntity val) => val -> ReaderT backend m (Maybe (Key val))
-- | update based on a uniquness constraint or insert
--
-- insert the new record if it does not exist update the existing record
-- that matches the uniqueness contraint
--
-- Throws an exception if there is more than 1 uniqueness contraint
upsert :: (PersistUnique backend, MonadIO m, PersistEntityBackend val ~ backend, PersistEntity val) => val -> [Update val] -> ReaderT backend m (Entity val)
-- | A modification of getBy, which takes the PersistEntity
-- itself instead of a Unique record. Returns a record matching
-- one of the unique keys. This function makes the most sense on
-- entities with a single Unique constructor.
getByValue :: (MonadIO m, PersistEntity record, PersistUnique backend, PersistEntityBackend record ~ backend) => record -> ReaderT backend m (Maybe (Entity record))
-- | Insert a value, checking for conflicts with any unique constraints. If
-- a duplicate exists in the database, it is returned as Left.
-- Otherwise, the new 'Key is returned as Right.
insertBy :: (MonadIO m, PersistEntity val, PersistUnique backend, PersistEntityBackend val ~ backend) => val -> ReaderT backend m (Either (Entity val) (Key val))
-- | Attempt to replace the record of the given key with the given new
-- record. First query the unique fields to make sure the replacement
-- maintains uniqueness constraints. Return Nothing if the
-- replacement was made. If uniqueness is violated, return a Just
-- with the Unique violation
--
-- Since 1.2.2.0
replaceUnique :: (MonadIO m, Eq record, Eq (Unique record), PersistEntityBackend record ~ backend, PersistEntity record, PersistUnique backend) => Key record -> record -> ReaderT backend m (Maybe (Unique record))
-- | Check whether there are any conflicts for unique keys with this entity
-- and existing entities in the database.
--
-- Returns Nothing if the entity would be unique, and could thus
-- safely be inserted. on a conflict returns the conflicting key
checkUnique :: (MonadIO m, PersistEntityBackend record ~ backend, PersistEntity record, PersistUnique backend) => record -> ReaderT backend m (Maybe (Unique record))
-- | Return the single unique key for a record
onlyUnique :: (MonadIO m, PersistEntity val, PersistUnique backend, PersistEntityBackend val ~ backend) => val -> ReaderT backend m (Unique val)
class PersistStore backend => PersistQuery backend where selectFirst filts opts = do { srcRes <- selectSourceRes filts ((LimitTo 1) : opts); liftIO $ with srcRes ($$ head) }
-- | Update individual fields on any record matching the given criterion.
updateWhere :: (PersistQuery backend, MonadIO m, PersistEntity val, backend ~ PersistEntityBackend val) => [Filter val] -> [Update val] -> ReaderT backend m ()
-- | Delete all records matching the given criterion.
deleteWhere :: (PersistQuery backend, MonadIO m, PersistEntity val, backend ~ PersistEntityBackend val) => [Filter val] -> ReaderT backend m ()
-- | Get all records matching the given criterion in the specified order.
-- Returns also the identifiers.
selectSourceRes :: (PersistQuery backend, PersistEntity val, PersistEntityBackend val ~ backend, MonadIO m1, MonadIO m2) => [Filter val] -> [SelectOpt val] -> ReaderT backend m1 (Acquire (Source m2 (Entity val)))
-- | get just the first record for the criterion
selectFirst :: (PersistQuery backend, MonadIO m, PersistEntity val, backend ~ PersistEntityBackend val) => [Filter val] -> [SelectOpt val] -> ReaderT backend m (Maybe (Entity val))
-- | Get the Keys of all records matching the given criterion.
selectKeysRes :: (PersistQuery backend, MonadIO m1, MonadIO m2, PersistEntity val, backend ~ PersistEntityBackend val) => [Filter val] -> [SelectOpt val] -> ReaderT backend m1 (Acquire (Source m2 (Key val)))
-- | The total number of records fulfilling the given criterion.
count :: (PersistQuery backend, MonadIO m, PersistEntity val, backend ~ PersistEntityBackend val) => [Filter val] -> ReaderT backend m Int
-- | Get all records matching the given criterion in the specified order.
-- Returns also the identifiers.
selectSource :: (PersistQuery backend, MonadResource m, PersistEntity val, PersistEntityBackend val ~ backend, MonadReader env m, HasPersistBackend env backend) => [Filter val] -> [SelectOpt val] -> Source m (Entity val)
-- | Get the Keys of all records matching the given criterion.
selectKeys :: (PersistQuery backend, MonadResource m, PersistEntity val, backend ~ PersistEntityBackend val, MonadReader env m, HasPersistBackend env backend) => [Filter val] -> [SelectOpt val] -> Source m (Key val)
-- | Call selectSource but return the result as a list.
selectList :: (MonadIO m, PersistEntity val, PersistQuery backend, PersistEntityBackend val ~ backend) => [Filter val] -> [SelectOpt val] -> ReaderT backend m [Entity val]
-- | Call selectKeys but return the result as a list.
selectKeysList :: (MonadIO m, PersistEntity val, PersistQuery backend, PersistEntityBackend val ~ backend) => [Filter val] -> [SelectOpt val] -> ReaderT backend m [Key val]
class (PersistStore backend, PersistEntity record, backend ~ PersistEntityBackend record) => DeleteCascade record backend
deleteCascade :: (DeleteCascade record backend, MonadIO m) => Key record -> ReaderT backend m ()
deleteCascadeWhere :: (MonadIO m, DeleteCascade record backend, PersistQuery backend) => [Filter record] -> ReaderT backend m ()
-- | Persistent serialized Haskell records to the database. A Database
-- Entity (A row in SQL, a document in MongoDB, etc) corresponds
-- to a Key plus a Haskell record.
--
-- For every Haskell record type stored in the database there is a
-- corresponding PersistEntity instance. An instance of
-- PersistEntity contains meta-data for the record. PersistEntity also
-- helps abstract over different record types. That way the same query
-- interface can return a PersistEntity, with each query returning
-- different types of Haskell records.
--
-- Some advanced type system capabilities are used to make this process
-- type-safe. Persistent users usually don't need to understand the class
-- associated data and functions.
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 :: * -> * data Unique record where {
type family PersistEntityBackend record;
data family Key record;
data family EntityField record :: * -> *;
data family Unique record;
}
-- | a lower-level key operation
keyToValues :: PersistEntity record => Key record -> [PersistValue]
-- | a lower-level key operation
keyFromValues :: PersistEntity record => [PersistValue] -> Either Text (Key record)
-- | a meta-operation to retrieve the Key EntityField
persistIdField :: PersistEntity record => EntityField record (Key record)
-- | retrieve the EntityDef meta-data for the record
entityDef :: (PersistEntity record, Monad m) => m record -> EntityDef
-- | return meta-data for a given EntityField
persistFieldDef :: PersistEntity record => EntityField record typ -> FieldDef
-- | A meta-operation to get the database fields of a record
toPersistFields :: PersistEntity record => record -> [SomePersistField]
-- | A lower-level operation to convert from database values to a Haskell
-- record
fromPersistValues :: PersistEntity record => [PersistValue] -> Either Text record
-- | A meta operation to retrieve all the Unique keys
persistUniqueKeys :: PersistEntity record => record -> [Unique record]
-- | A lower level operation
persistUniqueToFieldNames :: PersistEntity record => Unique record -> [(HaskellName, DBName)]
-- | A lower level operation
persistUniqueToValues :: PersistEntity record => Unique record -> [PersistValue]
-- | Use a PersistField as a lens
fieldLens :: PersistEntity record => EntityField record field -> (forall f. Functor f => (field -> f field) -> Entity record -> f (Entity record))
-- | A value which can be marshalled to and from a PersistValue.
class PersistField a
toPersistValue :: PersistField a => a -> PersistValue
fromPersistValue :: PersistField a => PersistValue -> Either Text a
-- | 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.
class PersistConfig c where type PersistConfigBackend c :: (* -> *) -> * -> * type PersistConfigPool c applyEnv = return where {
type family PersistConfigBackend c :: (* -> *) -> * -> *;
type family PersistConfigPool c;
}
-- | Load the config settings from a Value, most likely taken from a
-- YAML config file.
loadConfig :: PersistConfig c => Value -> Parser c
-- | Modify the config settings based on environment variables.
applyEnv :: PersistConfig c => c -> IO c
-- | Create a new connection pool based on the given config settings.
createPoolConfig :: PersistConfig c => c -> IO (PersistConfigPool c)
-- | Run a database action by taking a connection from the pool.
runPool :: (PersistConfig c, MonadBaseControl IO m, MonadIO m) => c -> PersistConfigBackend c m a -> PersistConfigPool c -> m a
entityValues :: PersistEntity record => Entity record -> [PersistValue]
class HasPersistBackend env backend | env -> backend
persistBackend :: HasPersistBackend env backend => env -> backend
liftPersist :: (MonadReader env m, HasPersistBackend env backend, MonadIO m) => ReaderT backend IO a -> m a
-- | Predefined toJSON. The resulting JSON looks like {"key":
-- 1, "value": {"name": ...}}.
--
-- The typical usage is:
--
--
-- instance ToJSON (Entity User) where
-- toJSON = keyValueEntityToJSON
--
keyValueEntityToJSON :: (PersistEntity record, ToJSON record, ToJSON (Key record)) => Entity record -> Value
-- | Predefined parseJSON. The input JSON looks like {"key":
-- 1, "value": {"name": ...}}.
--
-- The typical usage is:
--
--
-- instance FromJSON (Entity User) where
-- parseJSON = keyValueEntityFromJSON
--
keyValueEntityFromJSON :: (PersistEntity record, FromJSON record, FromJSON (Key record)) => Value -> Parser (Entity record)
-- | Predefined toJSON. The resulting JSON looks like {"id":
-- 1, "name": ...}.
--
-- The typical usage is:
--
--
-- instance ToJSON (Entity User) where
-- toJSON = entityIdToJSON
--
entityIdToJSON :: (PersistEntity record, ToJSON record, ToJSON (Key record)) => Entity record -> Value
-- | Predefined parseJSON. The input JSON looks like {"id": 1,
-- "name": ...}.
--
-- The typical usage is:
--
--
-- instance FromJSON (Entity User) where
-- parseJSON = entityIdFromJSON
--
entityIdFromJSON :: (PersistEntity record, FromJSON record, FromJSON (Key record)) => Value -> Parser (Entity record)
-- | Convenience function for getting a free PersistField instance
-- from a type with JSON instances.
--
-- Example usage in combination withfromPersistValueJSON:
--
--
-- instance PersistField MyData where
-- fromPersistValue = fromPersistValueJSON
-- toPersistValue = toPersistValueJSON
--
toPersistValueJSON :: ToJSON a => a -> PersistValue
-- | Convenience function for getting a free PersistField instance
-- from a type with JSON instances. The JSON parser used will accept JSON
-- values other that object and arrays. So, if your instance serializes
-- the data to a JSON string, this will still work.
--
-- Example usage in combination withtoPersistValueJSON:
--
--
-- instance PersistField MyData where
-- fromPersistValue = fromPersistValueJSON
-- toPersistValue = toPersistValueJSON
--
fromPersistValueJSON :: FromJSON a => PersistValue -> Either Text a
module Database.Persist
-- | assign a field a value
(=.) :: forall v typ. PersistField typ => EntityField v typ -> typ -> Update v
infixr 3 =.
-- | assign a field by addition (+=)
(+=.) :: forall v typ. PersistField typ => EntityField v typ -> typ -> Update v
infixr 3 +=.
-- | assign a field by subtraction (-=)
(-=.) :: forall v typ. PersistField typ => EntityField v typ -> typ -> Update v
infixr 3 -=.
-- | assign a field by multiplication (*=)
(*=.) :: forall v typ. PersistField typ => EntityField v typ -> typ -> Update v
infixr 3 *=.
-- | assign a field by division (/=)
(/=.) :: forall v typ. PersistField typ => EntityField v typ -> typ -> Update v
infixr 3 /=.
(==.) :: forall v typ. PersistField typ => EntityField v typ -> typ -> Filter v
infix 4 ==.
(!=.) :: forall v typ. PersistField typ => EntityField v typ -> typ -> Filter v
infix 4 !=.
(<.) :: forall v typ. PersistField typ => EntityField v typ -> typ -> Filter v
infix 4 <.
(>.) :: forall v typ. PersistField typ => EntityField v typ -> typ -> Filter v
infix 4 >.
(<=.) :: forall v typ. PersistField typ => EntityField v typ -> typ -> Filter v
infix 4 <=.
(>=.) :: forall v typ. PersistField typ => EntityField v typ -> typ -> Filter v
infix 4 >=.
-- | In
(<-.) :: forall v typ. PersistField typ => EntityField v typ -> [typ] -> Filter v
infix 4 <-.
-- | NotIn
(/<-.) :: forall v typ. PersistField typ => EntityField v typ -> [typ] -> Filter v
infix 4 /<-.
-- | the OR of two lists of filters. For example: selectList([PersonAge
-- >. 25, PersonAge 30] ||. [PersonIncome. 15000, PersonIncome
-- <. 25000]) [] will filter records where a person's age is between
-- (25 and 30) OR a person's income is between (15,000 and 25000). If you
-- are looking for an &&. operator to do (A AND B AND (C OR D))
-- you can use the ++ operator instead as there is no &&. For
-- example: selectList([PersonAge >. 25, PersonAge <. 30] ++
-- ([PersonCategory ==. 1] ||. [PersonCategory ==. 5])) [] will filter
-- records where a person's age is between (25 and 30) AND (person's
-- category is either 1 or 5)
(||.) :: forall v. [Filter v] -> [Filter v] -> [Filter v]
infixl 3 ||.
listToJSON :: [PersistValue] -> Text
mapToJSON :: [(Text, PersistValue)] -> Text
toJsonText :: ToJSON j => j -> Text
getPersistMap :: PersistValue -> Either Text [(Text, PersistValue)]
limitOffsetOrder :: PersistEntity val => [SelectOpt val] -> (Int, Int, [SelectOpt val])
module Database.Persist.Sql.Util
parseEntityValues :: PersistEntity record => EntityDef -> [PersistValue] -> Either Text (Entity record)
entityColumnNames :: EntityDef -> SqlBackend -> [Sql]
keyAndEntityColumnNames :: EntityDef -> SqlBackend -> [Sql]
entityColumnCount :: EntityDef -> Int
isIdField :: PersistEntity record => EntityField record typ -> Bool
hasCompositeKey :: EntityDef -> Bool
dbIdColumns :: SqlBackend -> EntityDef -> [Text]
dbIdColumnsEsc :: (DBName -> Text) -> EntityDef -> [Text]
dbColumns :: SqlBackend -> EntityDef -> [Text]
module Database.Persist.Sql
data InsertSqlResult
ISRSingle :: Text -> InsertSqlResult
ISRInsertGet :: Text -> Text -> InsertSqlResult
ISRManyKeys :: Text -> [PersistValue] -> InsertSqlResult
-- | Deprecated synonym for SqlBackend.
-- | Deprecated: Please use SqlBackend instead
type Connection = SqlBackend
data SqlBackend
SqlBackend :: (Text -> IO Statement) -> (EntityDef -> [PersistValue] -> InsertSqlResult) -> Maybe (EntityDef -> [[PersistValue]] -> InsertSqlResult) -> IORef (Map Text Statement) -> IO () -> ([EntityDef] -> (Text -> IO Statement) -> EntityDef -> IO (Either [Text] [(Bool, Text)])) -> ((Text -> IO Statement) -> IO ()) -> ((Text -> IO Statement) -> IO ()) -> ((Text -> IO Statement) -> IO ()) -> (DBName -> Text) -> Text -> Text -> ((Int, Int) -> Bool -> Text -> Text) -> LogFunc -> SqlBackend
[connPrepare] :: SqlBackend -> Text -> IO Statement
-- | table name, column names, id name, either 1 or 2 statements to run
[connInsertSql] :: SqlBackend -> EntityDef -> [PersistValue] -> InsertSqlResult
-- | SQL for inserting many rows and returning their primary keys, for
-- backends that support this functioanlity. If Nothing, rows will
-- be inserted one-at-a-time using connInsertSql.
[connInsertManySql] :: SqlBackend -> Maybe (EntityDef -> [[PersistValue]] -> InsertSqlResult)
[connStmtMap] :: SqlBackend -> IORef (Map Text Statement)
[connClose] :: SqlBackend -> IO ()
[connMigrateSql] :: SqlBackend -> [EntityDef] -> (Text -> IO Statement) -> EntityDef -> IO (Either [Text] [(Bool, Text)])
[connBegin] :: SqlBackend -> (Text -> IO Statement) -> IO ()
[connCommit] :: SqlBackend -> (Text -> IO Statement) -> IO ()
[connRollback] :: SqlBackend -> (Text -> IO Statement) -> IO ()
[connEscapeName] :: SqlBackend -> DBName -> Text
[connNoLimit] :: SqlBackend -> Text
[connRDBMS] :: SqlBackend -> Text
[connLimitOffset] :: SqlBackend -> (Int, Int) -> Bool -> Text -> Text
[connLogFunc] :: SqlBackend -> LogFunc
type LogFunc = Loc -> LogSource -> LogLevel -> LogStr -> IO ()
data Statement
Statement :: IO () -> IO () -> ([PersistValue] -> IO Int64) -> (forall m. MonadIO m => [PersistValue] -> Acquire (Source m [PersistValue])) -> Statement
[stmtFinalize] :: Statement -> IO ()
[stmtReset] :: Statement -> IO ()
[stmtExecute] :: Statement -> [PersistValue] -> IO Int64
[stmtQuery] :: Statement -> forall m. MonadIO m => [PersistValue] -> Acquire (Source m [PersistValue])
data Column
Column :: !DBName -> !Bool -> !SqlType -> !(Maybe Text) -> !(Maybe DBName) -> !(Maybe Integer) -> !(Maybe (DBName, DBName)) -> Column
[cName] :: Column -> !DBName
[cNull] :: Column -> !Bool
[cSqlType] :: Column -> !SqlType
[cDefault] :: Column -> !(Maybe Text)
[cDefaultConstraintName] :: Column -> !(Maybe DBName)
[cMaxLen] :: Column -> !(Maybe Integer)
[cReference] :: Column -> !(Maybe (DBName, DBName))
data PersistentSqlException
StatementAlreadyFinalized :: Text -> PersistentSqlException
Couldn'tGetSQLConnection :: PersistentSqlException
type SqlPersistT = ReaderT SqlBackend
-- | Deprecated: Please use SqlPersistT instead
type SqlPersist = SqlPersistT
type SqlPersistM = SqlPersistT (NoLoggingT (ResourceT IO))
type Sql = Text
type CautiousMigration = [(Bool, Sql)]
type Migration = WriterT [Text] (WriterT CautiousMigration (ReaderT SqlBackend IO)) ()
type ConnectionPool = Pool SqlBackend
-- | A single column (see rawSql). Any PersistField may
-- be used here, including PersistValue (which does not do any
-- processing).
newtype Single a
Single :: a -> Single a
[unSingle] :: Single a -> a
-- | Class for data types that may be retrived from a rawSql
-- query.
class RawSql a
-- | Number of columns that this data type needs and the list of
-- substitutions for SELECT placeholders ??.
rawSqlCols :: RawSql a => (DBName -> Text) -> a -> (Int, [Text])
-- | A string telling the user why the column count is what it is.
rawSqlColCountReason :: RawSql a => a -> String
-- | Transform a row of the result into the data type.
rawSqlProcessRow :: RawSql a => [PersistValue] -> Either Text a
class PersistField a => PersistFieldSql a
sqlType :: PersistFieldSql a => Proxy a -> SqlType
-- | Get a connection from the pool, run the given action, and then return
-- the connection to the pool.
--
-- Note: This function previously timed out after 2 seconds, but this
-- behavior was buggy and caused more problems than it solved. Since
-- version 2.1.2, it performs no timeout checks.
runSqlPool :: MonadBaseControl IO m => SqlPersistT m a -> Pool SqlBackend -> m a
-- | Like withResource, but times out the operation if resource
-- allocation does not complete within the given timeout period.
--
-- Since 2.0.0
withResourceTimeout :: forall a m b. (MonadBaseControl IO m) => Int -> Pool a -> (a -> m b) -> m (Maybe b)
runSqlConn :: MonadBaseControl IO m => SqlPersistT m a -> SqlBackend -> m a
runSqlPersistM :: SqlPersistM a -> SqlBackend -> IO a
runSqlPersistMPool :: SqlPersistM a -> Pool SqlBackend -> IO a
liftSqlPersistMPool :: MonadIO m => SqlPersistM a -> Pool SqlBackend -> m a
withSqlPool :: (MonadIO m, MonadLogger m, MonadBaseControl IO m) => (LogFunc -> IO SqlBackend) -> Int -> (Pool SqlBackend -> m a) -> m a
createSqlPool :: (MonadIO m, MonadLogger m, MonadBaseControl IO m) => (LogFunc -> IO SqlBackend) -> Int -> m (Pool SqlBackend)
askLogFunc :: forall m. (MonadBaseControl IO m, MonadLogger m) => m LogFunc
withSqlConn :: (MonadIO m, MonadBaseControl IO m, MonadLogger m) => (LogFunc -> IO SqlBackend) -> (SqlBackend -> m a) -> m a
close' :: SqlBackend -> IO ()
parseMigration :: MonadIO m => Migration -> ReaderT SqlBackend m (Either [Text] CautiousMigration)
parseMigration' :: MonadIO m => Migration -> ReaderT SqlBackend m (CautiousMigration)
printMigration :: MonadIO m => Migration -> ReaderT SqlBackend m ()
showMigration :: MonadIO m => Migration -> ReaderT SqlBackend m [Text]
getMigration :: MonadIO m => Migration -> ReaderT SqlBackend m [Sql]
runMigration :: MonadIO m => Migration -> ReaderT SqlBackend m ()
-- | Same as runMigration, but returns a list of the SQL commands
-- executed instead of printing them to stderr.
runMigrationSilent :: (MonadBaseControl IO m, MonadIO m) => Migration -> ReaderT SqlBackend m [Text]
runMigrationUnsafe :: MonadIO m => Migration -> ReaderT SqlBackend m ()
migrate :: [EntityDef] -> EntityDef -> Migration
withRawQuery :: MonadIO m => Text -> [PersistValue] -> Sink [PersistValue] IO a -> ReaderT SqlBackend m a
toSqlKey :: ToBackendKey SqlBackend record => Int64 -> Key record
fromSqlKey :: ToBackendKey SqlBackend record => Key record -> Int64
-- | get the SQL string for the field that an EntityField represents Useful
-- for raw SQL queries
--
-- Your backend may provide a more convenient fieldName function which
-- does not operate in a Monad
getFieldName :: forall record typ m. (PersistEntity record, PersistEntityBackend record ~ SqlBackend, Monad m) => EntityField record typ -> ReaderT SqlBackend m Text
-- | get the SQL string for the table that a PeristEntity represents Useful
-- for raw SQL queries
--
-- Your backend may provide a more convenient tableName function which
-- does not operate in a Monad
getTableName :: forall record m. (PersistEntity record, PersistEntityBackend record ~ SqlBackend, Monad m) => record -> ReaderT SqlBackend m Text
-- | useful for a backend to implement tableName by adding escaping
tableDBName :: forall record. (PersistEntity record, PersistEntityBackend record ~ SqlBackend) => record -> DBName
-- | useful for a backend to implement fieldName by adding escaping
fieldDBName :: forall record typ. (PersistEntity record) => EntityField record typ -> DBName
rawQuery :: (MonadResource m, MonadReader env m, HasPersistBackend env SqlBackend) => Text -> [PersistValue] -> Source m [PersistValue]
rawQueryRes :: (MonadIO m1, MonadIO m2) => Text -> [PersistValue] -> ReaderT SqlBackend m1 (Acquire (Source m2 [PersistValue]))
-- | Execute a raw SQL statement
rawExecute :: MonadIO m => Text -> [PersistValue] -> ReaderT SqlBackend m ()
-- | Execute a raw SQL statement and return the number of rows it has
-- modified.
rawExecuteCount :: MonadIO m => Text -> [PersistValue] -> ReaderT SqlBackend m Int64
-- | Execute a raw SQL statement and return its results as a list.
--
-- If you're using Entitys (which is quite likely), then
-- you must use entity selection placeholders (double question
-- mark, ??). These ?? placeholders are then replaced
-- for the names of the columns that we need for your entities. You'll
-- receive an error if you don't use the placeholders. Please see the
-- Entitys documentation for more details.
--
-- You may put value placeholders (question marks, ?) in your
-- SQL query. These placeholders are then replaced by the values you pass
-- on the second parameter, already correctly escaped. You may want to
-- use toPersistValue to help you constructing the placeholder
-- values.
--
-- Since you're giving a raw SQL statement, you don't get any guarantees
-- regarding safety. If rawSql is not able to parse the results of
-- your query back, then an exception is raised. However, most common
-- problems are mitigated by using the entity selection placeholder
-- ??, and you shouldn't see any error at all if you're not
-- using Single.
--
-- Some example of rawSql based on this schema:
--
--
-- share [mkPersist sqlSettings, mkMigrate "migrateAll"] [persistLowerCase|
-- Person
-- name String
-- age Int Maybe
-- deriving Show
-- BlogPost
-- title String
-- authorId PersonId
-- deriving Show
-- |]
--
--
-- Examples based on the above schema:
--
--
-- getPerson :: MonadIO m => ReaderT SqlBackend m [Entity Person]
-- getPerson = rawSql "select ?? from person where name=?" [PersistText "john"]
--
-- getAge :: MonadIO m => ReaderT SqlBackend m [Single Int]
-- getAge = rawSql "select person.age from person where name=?" [PersistText "john"]
--
-- getAgeName :: MonadIO m => ReaderT SqlBackend m [(Single Int, Single Text)]
-- getAgeName = rawSql "select person.age, person.name from person where name=?" [PersistText "john"]
--
-- getPersonBlog :: MonadIO m => ReaderT SqlBackend m [(Entity Person, Entity BlogPost)]
-- getPersonBlog = rawSql "select ??,?? from person,blog_post where person.id = blog_post.author_id" []
--
--
-- Minimal working program for PostgreSQL backend based on the above
-- concepts:
--
--
-- {-# LANGUAGE EmptyDataDecls #-}
-- {-# LANGUAGE FlexibleContexts #-}
-- {-# LANGUAGE GADTs #-}
-- {-# LANGUAGE GeneralizedNewtypeDeriving #-}
-- {-# LANGUAGE MultiParamTypeClasses #-}
-- {-# LANGUAGE OverloadedStrings #-}
-- {-# LANGUAGE QuasiQuotes #-}
-- {-# LANGUAGE TemplateHaskell #-}
-- {-# LANGUAGE TypeFamilies #-}
--
-- import Control.Monad.IO.Class (liftIO)
-- import Control.Monad.Logger (runStderrLoggingT)
-- import Database.Persist
-- import Control.Monad.Reader
-- import Data.Text
-- import Database.Persist.Sql
-- import Database.Persist.Postgresql
-- import Database.Persist.TH
--
-- share [mkPersist sqlSettings, mkMigrate "migrateAll"] [persistLowerCase|
-- Person
-- name String
-- age Int Maybe
-- deriving Show
-- |]
--
-- conn = "host=localhost dbname=new_db user=postgres password=postgres port=5432"
--
-- getPerson :: MonadIO m => ReaderT SqlBackend m [Entity Person]
-- getPerson = rawSql "select ?? from person where name=?" [PersistText "sibi"]
--
-- liftSqlPersistMPool y x = liftIO (runSqlPersistMPool y x)
--
-- main :: IO ()
-- main = runStderrLoggingT $ withPostgresqlPool conn 10 $ liftSqlPersistMPool $ do
-- runMigration migrateAll
-- xs <- getPerson
-- liftIO (print xs)
--
rawSql :: (RawSql a, MonadIO m) => Text -> [PersistValue] -> ReaderT SqlBackend m [a]
-- | Same as deleteWhere, but returns the number of rows affected.
--
-- Since 1.1.5
deleteWhereCount :: (PersistEntity val, MonadIO m, PersistEntityBackend val ~ SqlBackend) => [Filter val] -> ReaderT SqlBackend m Int64
-- | Same as updateWhere, but returns the number of rows affected.
--
-- Since 1.1.5
updateWhereCount :: (PersistEntity val, MonadIO m, SqlBackend ~ PersistEntityBackend val) => [Filter val] -> [Update val] -> ReaderT SqlBackend m Int64
-- | Commit the current transaction and begin a new one.
--
-- Since 1.2.0
transactionSave :: MonadIO m => ReaderT SqlBackend m ()
-- | Roll back the current transaction and begin a new one.
--
-- Since 1.2.0
transactionUndo :: MonadIO m => ReaderT SqlBackend m ()
getStmtConn :: SqlBackend -> Text -> IO Statement
-- | Create the list of columns for the given entity.
mkColumns :: [EntityDef] -> EntityDef -> ([Column], [UniqueDef], [ForeignDef])
defaultAttribute :: [Attr] -> Maybe Text
-- | Generates sql for limit and offset for postgres, sqlite and mysql.
decorateSQLWithLimitOffset :: Text -> (Int, Int) -> Bool -> Text -> Text