persistent-1.2.0.1: Type-safe, multi-backend data serialization.

Safe HaskellNone

Database.Persist.Class

Synopsis

Documentation

class (PersistStore m, PersistEntity a, PersistEntityBackend a ~ PersistMonadBackend m) => DeleteCascade a m where

Methods

deleteCascade :: Key a -> m ()

class PersistEntity val where

A single database entity. For example, if writing a blog application, a blog entry would be an entry, containing fields such as title and content.

Associated Types

data EntityField val :: * -> *

Parameters: val and datatype of the field

type PersistEntityBackend val

data Unique val

Unique keys in existence on this entity.

Methods

persistFieldDef :: EntityField val typ -> FieldDef SqlType

entityDef :: Monad m => m val -> EntityDef SqlType

toPersistFields :: val -> [SomePersistField]

fromPersistValues :: [PersistValue] -> Either Text val

persistUniqueToFieldNames :: Unique val -> [(HaskellName, DBName)]

persistUniqueToValues :: Unique val -> [PersistValue]

persistUniqueKeys :: val -> [Unique val]

persistIdField :: EntityField val (Key val)

fieldLens :: EntityField val field -> forall f. Functor f => (field -> f field) -> Entity val -> f (Entity val)

class PersistStore m => PersistQuery m where

Methods

update :: (PersistEntity val, PersistEntityBackend val ~ PersistMonadBackend m) => Key val -> [Update val] -> m ()

Update individual fields on a specific record.

updateGet :: (PersistEntity val, PersistMonadBackend m ~ PersistEntityBackend val) => Key val -> [Update val] -> m val

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.

updateWhere :: (PersistEntity val, PersistEntityBackend val ~ PersistMonadBackend m) => [Filter val] -> [Update val] -> m ()

Update individual fields on any record matching the given criterion.

deleteWhere :: (PersistEntity val, PersistEntityBackend val ~ PersistMonadBackend m) => [Filter val] -> m ()

Delete all records matching the given criterion.

selectSource :: (PersistEntity val, PersistEntityBackend val ~ PersistMonadBackend m) => [Filter val] -> [SelectOpt val] -> Source m (Entity val)

Get all records matching the given criterion in the specified order. Returns also the identifiers.

selectFirst :: (PersistEntity val, PersistEntityBackend val ~ PersistMonadBackend m) => [Filter val] -> [SelectOpt val] -> m (Maybe (Entity val))

get just the first record for the criterion

selectKeys :: (PersistEntity val, PersistEntityBackend val ~ PersistMonadBackend m) => [Filter val] -> [SelectOpt val] -> Source m (Key val)

Get the Keys of all records matching the given criterion.

count :: (PersistEntity val, PersistEntityBackend val ~ PersistMonadBackend m) => [Filter val] -> m Int

The total number of records fulfilling the given criterion.

Instances

class PersistStore m => PersistUnique m where

Queries against unique keys (other than the id).

Please read the general Persistent documentation to learn how to create Unique keys. SQL backends automatically create uniqueness constraints, but for MongoDB you must place a unique index on the field.

Methods

getBy :: (PersistEntityBackend val ~ PersistMonadBackend m, PersistEntity val) => Unique val -> m (Maybe (Entity val))

Get a record by unique key, if available. Returns also the identifier.

deleteBy :: (PersistEntityBackend val ~ PersistMonadBackend m, PersistEntity val) => Unique val -> m ()

Delete a specific record by unique key. Does nothing if no record matches.

insertUnique :: (PersistEntityBackend val ~ PersistMonadBackend m, PersistEntity val) => val -> m (Maybe (Key val))

Like insert, but returns Nothing when the record couldn't be inserted because of a uniqueness constraint.

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.

Associated Types

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

type PersistConfigPool c

Methods

loadConfig :: Value -> Parser c

Load the config settings from a Value, most likely taken from a YAML config file.

applyEnv :: c -> IO c

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

Run a database action by taking a connection from the pool.

Instances

class PersistField a where

A value which can be marshalled to and from a PersistValue.

Methods

toPersistValue :: a -> PersistValue

fromPersistValue :: PersistValue -> Either Text a

Instances

class MonadIO m => PersistStore m where

Associated Types

type PersistMonadBackend m

Methods

insert :: (PersistMonadBackend m ~ PersistEntityBackend val, PersistEntity val) => val -> m (Key val)

Create a new record in the database, returning an automatically created key (in SQL an auto-increment id).

insert_ :: (PersistMonadBackend m ~ PersistEntityBackend val, PersistEntity val) => val -> m ()

Same as insert, but doesn't return a Key.

insertKey :: (PersistMonadBackend m ~ PersistEntityBackend val, PersistEntity val) => Key val -> val -> m ()

Create a new record in the database using the given key.

repsert :: (PersistMonadBackend m ~ PersistEntityBackend val, PersistEntity val) => Key val -> val -> 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.

replace :: (PersistMonadBackend m ~ PersistEntityBackend val, PersistEntity val) => Key val -> val -> 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.

delete :: (PersistMonadBackend m ~ PersistEntityBackend val, PersistEntity val) => Key val -> m ()

Delete a specific record by identifier. Does nothing if record does not exist.

get :: (PersistMonadBackend m ~ PersistEntityBackend val, PersistEntity val) => Key val -> m (Maybe val)

Get a record by identifier, if available.

Instances