Database.Persist.Postgresql

A postgresql backend for persistent.

Documentation

withPostgresqlPool

Arguments

:: (MonadBaseControl IO m, MonadLogger m, MonadIO m, IsSqlBackend backend)

=> ConnectionString

Connection string to the database.

-> Int

Number of connections to be kept open in the pool.

-> (Pool backend -> m a)

Action to be executed that uses the connection pool.

-> m a

Create a PostgreSQL connection pool and run the given action. The pool is properly released after the action finishes using it. Note that you should not use the given ConnectionPool outside the action since it may be already been released.

withPostgresqlConn :: (MonadIO m, MonadBaseControl IO m, MonadLogger m, IsSqlBackend backend) => ConnectionString -> (backend -> m a) -> m a

Same as withPostgresqlPool, but instead of opening a pool of connections, only one connection is opened.

createPostgresqlPool

Arguments

:: (MonadIO m, MonadBaseControl IO m, MonadLogger m, IsSqlBackend backend)

=> ConnectionString

Connection string to the database.

-> Int

Number of connections to be kept open in the pool.

-> m (Pool backend)

Create a PostgreSQL connection pool. Note that it's your responsibility to properly close the connection pool when unneeded. Use withPostgresqlPool for an automatic resource control.

createPostgresqlPoolModified

Arguments

:: (MonadIO m, MonadBaseControl IO m, MonadLogger m, IsSqlBackend backend)

=> (Connection -> IO ())

action to perform after connection is created

-> ConnectionString

Connection string to the database.

-> Int

Number of connections to be kept open in the pool.

-> m (Pool backend)

Same as createPostgresqlPool, but additionally takes a callback function for some connection-specific tweaking to be performed after connection creation. This could be used, for example, to change the schema. For more information, see:

https://groups.google.com/d/msg/yesodweb/qUXrEN_swEo/O0pFwqwQIdcJ

Since 2.1.3

module Database.Persist.Sql

type ConnectionString = ByteString

A libpq connection string. A simple example of connection string would be "host=localhost port=5432 user=test dbname=test password=test". Please read libpq's documentation at http://www.postgresql.org/docs/9.1/static/libpq-connect.html for more details on how to create such strings.

data PostgresConf

Information required to connect to a PostgreSQL database using persistent's generic facilities. These values are the same that are given to withPostgresqlPool.

Constructors

PostgresConf

Fields

• pgConnStr :: ConnectionString

  The connection string.

• pgPoolSize :: Int

  How many connections should be held on the connection pool.

Instances

Data PostgresConf

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> PostgresConf -> c PostgresConf

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c PostgresConf

toConstr :: PostgresConf -> Constr

dataTypeOf :: PostgresConf -> DataType

dataCast1 :: Typeable (* -> *) t => (forall d. Data d => c (t d)) -> Maybe (c PostgresConf)

dataCast2 :: Typeable (* -> * -> *) t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c PostgresConf)

gmapT :: (forall b. Data b => b -> b) -> PostgresConf -> PostgresConf

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> PostgresConf -> r

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> PostgresConf -> r

gmapQ :: (forall d. Data d => d -> u) -> PostgresConf -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> PostgresConf -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> PostgresConf -> m PostgresConf

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> PostgresConf -> m PostgresConf

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> PostgresConf -> m PostgresConf

Read PostgresConf

Methods

readsPrec :: Int -> ReadS PostgresConf

readList :: ReadS [PostgresConf]

readPrec :: ReadPrec PostgresConf

readListPrec :: ReadPrec [PostgresConf]

Show PostgresConf

Methods

showsPrec :: Int -> PostgresConf -> ShowS

show :: PostgresConf -> String

showList :: [PostgresConf] -> ShowS

FromJSON PostgresConf

Methods

parseJSON :: Value -> Parser PostgresConf

parseJSONList :: Value -> Parser [PostgresConf]

PersistConfig PostgresConf

Associated Types

type PersistConfigBackend PostgresConf :: (* -> *) -> * -> *

type PersistConfigPool PostgresConf :: *

Methods

loadConfig :: Value -> Parser PostgresConf

applyEnv :: PostgresConf -> IO PostgresConf

createPoolConfig :: PostgresConf -> IO (PersistConfigPool PostgresConf)

runPool :: (MonadBaseControl IO m, MonadIO m) => PostgresConf -> PersistConfigBackend PostgresConf m a -> PersistConfigPool PostgresConf -> m a

type PersistConfigPool PostgresConf

type PersistConfigPool PostgresConf = ConnectionPool

type PersistConfigBackend PostgresConf

type PersistConfigBackend PostgresConf = SqlPersistT

openSimpleConn :: IsSqlBackend backend => LogFunc -> Connection -> IO backend

Generate a Connection from a Connection

tableName :: PersistEntity record => record -> Text

get the SQL string for the table that a PeristEntity represents Useful for raw SQL queries

fieldName :: PersistEntity record => EntityField record typ -> Text

get the SQL string for the field that an EntityField represents Useful for raw SQL queries

mockMigration :: Migration -> IO ()

Mock a migration even when the database is not present. This function performs the same functionality of printMigration with the difference that an actualy database isn't needed for it.