Database.Persist.SqlBackend.Internal

Documentation

data SqlBackend

A SqlBackend represents a handle or connection to a database. It contains functions and values that allow databases to have more optimized implementations, as well as references that benefit performance and sharing.

Instead of using the SqlBackend constructor directly, use the mkSqlBackend function.

A SqlBackend is *not* thread-safe. You should not assume that a SqlBackend can be shared among threads and run concurrent queries. This *will* result in problems. Instead, you should create a Pool SqlBackend, known as a ConnectionPool, and pass that around in multi-threaded applications.

To run actions in the persistent library, you should use the runSqlConn function. If you're using a multithreaded application, use the runSqlPool function.

Constructors

SqlBackend

Fields

• connPrepare :: Text -> IO Statement

  This function should prepare a Statement in the target database, which should allow for efficient query reuse.

• connInsertSql :: EntityDef -> [PersistValue] -> InsertSqlResult

  This function generates the SQL and values necessary for performing an insert against the database.

• connInsertManySql :: Maybe (EntityDef -> [[PersistValue]] -> InsertSqlResult)

  SQL for inserting many rows and returning their primary keys, for backends that support this functionality. If Nothing, rows will be inserted one-at-a-time using SqlBackend.

• connUpsertSql :: Maybe (EntityDef -> NonEmpty (FieldNameHS, FieldNameDB) -> Text -> Text)

  Some databases support performing UPSERT _and_ RETURN entity in a single call.

  This field when set will be used to generate the UPSERT+RETURN sql given * an entity definition * updates to be run on unique key(s) collision

  When left as Nothing, we find the unique key from entity def before * trying to fetch an entity by said key * perform an update when result found, else issue an insert * return new entity from db

  Since: 2.6

• connPutManySql :: Maybe (EntityDef -> Int -> Text)

  Some databases support performing bulk UPSERT, specifically "insert or replace many records" in a single call.

  This field when set, given * an entity definition * number of records to be inserted should produce a PUT MANY sql with placeholders for records

  When left as Nothing, we default to using defaultPutMany.

  Since: 2.8.1

• connStmtMap :: StatementCache

  A reference to the cache of statements. Statements are keyed by the Text queries that generated them.

• connClose :: IO ()

  Close the underlying connection.

• connMigrateSql :: [EntityDef] -> (Text -> IO Statement) -> EntityDef -> IO (Either [Text] [(Bool, Text)])

  This function returns the migrations required to include the EntityDef parameter in the [EntityDef] database. This might include creating a new table if the entity is not present, or altering an existing table if it is.

• connBegin :: (Text -> IO Statement) -> Maybe IsolationLevel -> IO ()

  A function to begin a transaction for the underlying database.

• connCommit :: (Text -> IO Statement) -> IO ()

  A function to commit a transaction to the underlying database.

• connRollback :: (Text -> IO Statement) -> IO ()

  A function to roll back a transaction on the underlying database.

• connEscapeFieldName :: FieldNameDB -> Text

  A function to extract and escape the name of the column corresponding to the provided field.

  Since: 2.12.0.0

• connEscapeTableName :: EntityDef -> Text

  A function to extract and escape the name of the table corresponding to the provided entity. PostgreSQL uses this to support schemas.

  Since: 2.12.0.0

• connEscapeRawName :: Text -> Text

  A function to escape raw DB identifiers. MySQL uses backticks, while PostgreSQL uses quotes, and so on.

  Since: 2.12.0.0

• connNoLimit :: Text
• connRDBMS :: Text

  A tag displaying what database the SqlBackend is for. Can be used to differentiate features in downstream libraries for different database backends.

• connLimitOffset :: (Int, Int) -> Text -> Text

  Attach a 'LIMIT/OFFSET' clause to a SQL query. Note that LIMIT/OFFSET is problematic for performance, and indexed range queries are the superior way to offer pagination.

• connLogFunc :: LogFunc

  A log function for the SqlBackend to use.

• connMaxParams :: Maybe Int

  Some databases (probably only Sqlite) have a limit on how many question-mark parameters may be used in a statement

  Since: 2.6.1

• connRepsertManySql :: Maybe (EntityDef -> Int -> Text)

  Some databases support performing bulk an atomic+bulk INSERT where constraint conflicting entities can replace existing entities.

  This field when set, given * an entity definition * number of records to be inserted should produce a INSERT sql with placeholders for primary+record fields

  When left as Nothing, we default to using defaultRepsertMany.

  Since: 2.9.0

• connVault :: Vault

  Carry arbitrary payloads for the connection that may be used to propagate information into hooks.

• connHooks :: SqlBackendHooks

  Instrumentation hooks that may be used to track the behaviour of a backend.

Instances

PersistQueryRead SqlBackend

Defined in Database.Persist.Sql.Orphan.PersistQuery

Methods

selectSourceRes :: forall record (m1 :: Type -> Type) (m2 :: Type -> Type). (PersistRecordBackend record SqlBackend, MonadIO m1, MonadIO m2) => [Filter record] -> [SelectOpt record] -> ReaderT SqlBackend m1 (Acquire (ConduitM () (Entity record) m2 ()))

selectFirst :: forall (m :: Type -> Type) record. (MonadIO m, PersistRecordBackend record SqlBackend) => [Filter record] -> [SelectOpt record] -> ReaderT SqlBackend m (Maybe (Entity record))

selectKeysRes :: forall (m1 :: Type -> Type) (m2 :: Type -> Type) record. (MonadIO m1, MonadIO m2, PersistRecordBackend record SqlBackend) => [Filter record] -> [SelectOpt record] -> ReaderT SqlBackend m1 (Acquire (ConduitM () (Key record) m2 ()))

count :: forall (m :: Type -> Type) record. (MonadIO m, PersistRecordBackend record SqlBackend) => [Filter record] -> ReaderT SqlBackend m Int

exists :: forall (m :: Type -> Type) record. (MonadIO m, PersistRecordBackend record SqlBackend) => [Filter record] -> ReaderT SqlBackend m Bool

PersistQueryWrite SqlBackend

Defined in Database.Persist.Sql.Orphan.PersistQuery

Methods

updateWhere :: forall (m :: Type -> Type) record. (MonadIO m, PersistRecordBackend record SqlBackend) => [Filter record] -> [Update record] -> ReaderT SqlBackend m ()

deleteWhere :: forall (m :: Type -> Type) record. (MonadIO m, PersistRecordBackend record SqlBackend) => [Filter record] -> ReaderT SqlBackend m ()

HasPersistBackend SqlBackend

Defined in Database.Persist.SqlBackend.Internal

Associated Types

type BaseBackend SqlBackend

Methods

persistBackend :: SqlBackend -> BaseBackend SqlBackend

IsPersistBackend SqlBackend

Defined in Database.Persist.SqlBackend.Internal

Methods

mkPersistBackend :: BaseBackend SqlBackend -> SqlBackend

PersistCore SqlBackend

Defined in Database.Persist.Sql.Orphan.PersistStore

Associated Types

data BackendKey SqlBackend

PersistStoreRead SqlBackend

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

get :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record SqlBackend) => Key record -> ReaderT SqlBackend m (Maybe record)

getMany :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record SqlBackend) => [Key record] -> ReaderT SqlBackend m (Map (Key record) record)

PersistStoreWrite SqlBackend

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

insert :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record SqlBackend, SafeToInsert record) => record -> ReaderT SqlBackend m (Key record)

insert_ :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record SqlBackend, SafeToInsert record) => record -> ReaderT SqlBackend m ()

insertMany :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record SqlBackend, SafeToInsert record) => [record] -> ReaderT SqlBackend m [Key record]

insertMany_ :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record SqlBackend, SafeToInsert record) => [record] -> ReaderT SqlBackend m ()

insertEntityMany :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record SqlBackend) => [Entity record] -> ReaderT SqlBackend m ()

insertKey :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record SqlBackend) => Key record -> record -> ReaderT SqlBackend m ()

repsert :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record SqlBackend) => Key record -> record -> ReaderT SqlBackend m ()

repsertMany :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record SqlBackend) => [(Key record, record)] -> ReaderT SqlBackend m ()

replace :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record SqlBackend) => Key record -> record -> ReaderT SqlBackend m ()

delete :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record SqlBackend) => Key record -> ReaderT SqlBackend m ()

update :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record SqlBackend) => Key record -> [Update record] -> ReaderT SqlBackend m ()

updateGet :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record SqlBackend) => Key record -> [Update record] -> ReaderT SqlBackend m record

PersistUniqueRead SqlBackend

Defined in Database.Persist.Sql.Orphan.PersistUnique

Methods

getBy :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record SqlBackend) => Unique record -> ReaderT SqlBackend m (Maybe (Entity record))

PersistUniqueWrite SqlBackend

Defined in Database.Persist.Sql.Orphan.PersistUnique

Methods

deleteBy :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record SqlBackend) => Unique record -> ReaderT SqlBackend m ()

insertUnique :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record SqlBackend, SafeToInsert record) => record -> ReaderT SqlBackend m (Maybe (Key record))

upsert :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record SqlBackend, OnlyOneUniqueKey record, SafeToInsert record) => record -> [Update record] -> ReaderT SqlBackend m (Entity record)

upsertBy :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record SqlBackend, SafeToInsert record) => Unique record -> record -> [Update record] -> ReaderT SqlBackend m (Entity record)

putMany :: forall record (m :: Type -> Type). (MonadIO m, PersistRecordBackend record SqlBackend, SafeToInsert record) => [record] -> ReaderT SqlBackend m ()

BackendCompatible SqlBackend SqlReadBackend

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

projectBackend :: SqlReadBackend -> SqlBackend

BackendCompatible SqlBackend SqlWriteBackend

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

projectBackend :: SqlWriteBackend -> SqlBackend

BackendCompatible SqlBackend SqlBackend

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

projectBackend :: SqlBackend -> SqlBackend

FromJSON (BackendKey SqlBackend)

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

parseJSON :: Value -> Parser (BackendKey SqlBackend)

parseJSONList :: Value -> Parser [BackendKey SqlBackend]

ToJSON (BackendKey SqlBackend)

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

toJSON :: BackendKey SqlBackend -> Value

toEncoding :: BackendKey SqlBackend -> Encoding

toJSONList :: [BackendKey SqlBackend] -> Value

toEncodingList :: [BackendKey SqlBackend] -> Encoding

Bounded (BackendKey SqlBackend)

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

minBound :: BackendKey SqlBackend

maxBound :: BackendKey SqlBackend

Enum (BackendKey SqlBackend)

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

succ :: BackendKey SqlBackend -> BackendKey SqlBackend

pred :: BackendKey SqlBackend -> BackendKey SqlBackend

toEnum :: Int -> BackendKey SqlBackend

fromEnum :: BackendKey SqlBackend -> Int

enumFrom :: BackendKey SqlBackend -> [BackendKey SqlBackend]

enumFromThen :: BackendKey SqlBackend -> BackendKey SqlBackend -> [BackendKey SqlBackend]

enumFromTo :: BackendKey SqlBackend -> BackendKey SqlBackend -> [BackendKey SqlBackend]

enumFromThenTo :: BackendKey SqlBackend -> BackendKey SqlBackend -> BackendKey SqlBackend -> [BackendKey SqlBackend]

Generic (BackendKey SqlBackend)

Defined in Database.Persist.Sql.Orphan.PersistStore

Associated Types

type Rep (BackendKey SqlBackend) :: Type -> Type

Methods

from :: BackendKey SqlBackend -> Rep (BackendKey SqlBackend) x

to :: Rep (BackendKey SqlBackend) x -> BackendKey SqlBackend

Num (BackendKey SqlBackend)

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

(+) :: BackendKey SqlBackend -> BackendKey SqlBackend -> BackendKey SqlBackend

(-) :: BackendKey SqlBackend -> BackendKey SqlBackend -> BackendKey SqlBackend

(*) :: BackendKey SqlBackend -> BackendKey SqlBackend -> BackendKey SqlBackend

negate :: BackendKey SqlBackend -> BackendKey SqlBackend

abs :: BackendKey SqlBackend -> BackendKey SqlBackend

signum :: BackendKey SqlBackend -> BackendKey SqlBackend

fromInteger :: Integer -> BackendKey SqlBackend

Read (BackendKey SqlBackend)

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

readsPrec :: Int -> ReadS (BackendKey SqlBackend)

readList :: ReadS [BackendKey SqlBackend]

readPrec :: ReadPrec (BackendKey SqlBackend)

readListPrec :: ReadPrec [BackendKey SqlBackend]

Integral (BackendKey SqlBackend)

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

quot :: BackendKey SqlBackend -> BackendKey SqlBackend -> BackendKey SqlBackend

rem :: BackendKey SqlBackend -> BackendKey SqlBackend -> BackendKey SqlBackend

div :: BackendKey SqlBackend -> BackendKey SqlBackend -> BackendKey SqlBackend

mod :: BackendKey SqlBackend -> BackendKey SqlBackend -> BackendKey SqlBackend

quotRem :: BackendKey SqlBackend -> BackendKey SqlBackend -> (BackendKey SqlBackend, BackendKey SqlBackend)

divMod :: BackendKey SqlBackend -> BackendKey SqlBackend -> (BackendKey SqlBackend, BackendKey SqlBackend)

toInteger :: BackendKey SqlBackend -> Integer

Real (BackendKey SqlBackend)

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

toRational :: BackendKey SqlBackend -> Rational

Show (BackendKey SqlBackend)

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

showsPrec :: Int -> BackendKey SqlBackend -> ShowS

show :: BackendKey SqlBackend -> String

showList :: [BackendKey SqlBackend] -> ShowS

Eq (BackendKey SqlBackend)

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

(==) :: BackendKey SqlBackend -> BackendKey SqlBackend -> Bool

(/=) :: BackendKey SqlBackend -> BackendKey SqlBackend -> Bool

Ord (BackendKey SqlBackend)

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

compare :: BackendKey SqlBackend -> BackendKey SqlBackend -> Ordering

(<) :: BackendKey SqlBackend -> BackendKey SqlBackend -> Bool

(<=) :: BackendKey SqlBackend -> BackendKey SqlBackend -> Bool

(>) :: BackendKey SqlBackend -> BackendKey SqlBackend -> Bool

(>=) :: BackendKey SqlBackend -> BackendKey SqlBackend -> Bool

max :: BackendKey SqlBackend -> BackendKey SqlBackend -> BackendKey SqlBackend

min :: BackendKey SqlBackend -> BackendKey SqlBackend -> BackendKey SqlBackend

FromHttpApiData (BackendKey SqlBackend)

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

parseUrlPiece :: Text -> Either Text (BackendKey SqlBackend)

parseHeader :: ByteString -> Either Text (BackendKey SqlBackend)

parseQueryParam :: Text -> Either Text (BackendKey SqlBackend)

ToHttpApiData (BackendKey SqlBackend)

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

toUrlPiece :: BackendKey SqlBackend -> Text

toEncodedUrlPiece :: BackendKey SqlBackend -> Builder

toHeader :: BackendKey SqlBackend -> ByteString

toQueryParam :: BackendKey SqlBackend -> Text

PathPiece (BackendKey SqlBackend)

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

fromPathPiece :: Text -> Maybe (BackendKey SqlBackend)

toPathPiece :: BackendKey SqlBackend -> Text

PersistField (BackendKey SqlBackend)

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

toPersistValue :: BackendKey SqlBackend -> PersistValue

fromPersistValue :: PersistValue -> Either Text (BackendKey SqlBackend)

PersistFieldSql (BackendKey SqlBackend)

Defined in Database.Persist.Sql.Orphan.PersistStore

Methods

sqlType :: Proxy (BackendKey SqlBackend) -> SqlType

newtype BackendKey SqlBackend

Defined in Database.Persist.Sql.Orphan.PersistStore

newtype BackendKey SqlBackend = SqlBackendKey {

• unSqlBackendKey :: Int64

}

type BaseBackend SqlBackend

Defined in Database.Persist.SqlBackend.Internal

type BaseBackend SqlBackend = SqlBackend

type Rep (BackendKey SqlBackend)

Defined in Database.Persist.Sql.Orphan.PersistStore

type Rep (BackendKey SqlBackend) = D1 ('MetaData "BackendKey" "Database.Persist.Sql.Orphan.PersistStore" "persistent-2.14.4.4-BNX9uN4LzYq9FAgcgBYgUn" 'True) (C1 ('MetaCons "SqlBackendKey" 'PrefixI 'True) (S1 ('MetaSel ('Just "unSqlBackendKey") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Int64)))

newtype SqlBackendHooks

Constructors

SqlBackendHooks

Fields

• hookGetStatement :: SqlBackend -> Text -> Statement -> IO Statement

emptySqlBackendHooks :: SqlBackendHooks

mkSqlBackend :: MkSqlBackendArgs -> SqlBackend

A function for creating a value of the SqlBackend type. You should prefer to use this instead of the constructor for SqlBackend, because default values for this will be provided for new fields on the record when new functionality is added.

Since: 2.13.0.0