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|
{-# LANGUAGE ConstraintKinds #-}
-- | This module exports all of the type classes in @persistent@ for operating
-- on the database backends.
--
-- @persistent@ offers methods that are abstract in the specific @backend@ type.
-- For SQL databases, this wil be 'Database.Persist.SqlBackend.SqlBackend'.
-- Other database backends will define their own types.
--
-- Methods and functions in this module have examples documented under an
-- "Example Usage" thing, that you need to click on to expand.
--
module Database.Persist.Class
(
-- * PersistStore
-- | The 'PersistStore', 'PersistStoreRead', and 'PersistStoreWrite' type
-- classes are used to define basic operations on the database. A database
-- that implements these classes is capable of being used as a simple
-- key-value store.
--
-- All the examples present here will be explained based on these schemas, datasets and functions:
--
-- = schema-1
--
-- #schema-persist-store-1#
--
-- > share [mkPersist sqlSettings, mkMigrate "migrateAll"] [persistLowerCase|
-- > User
-- > name String
-- > age Int
-- > deriving Show
-- > |]
--
-- = dataset-1
--
-- #dataset-persist-store-1#
--
-- > +----+-------+-----+
-- > | id | name | age |
-- > +----+-------+-----+
-- > | 1 | SPJ | 40 |
-- > +----+-------+-----+
-- > | 2 | Simon | 41 |
-- > +----+-------+-----+
PersistStore
, PersistStoreRead (..)
, PersistStoreWrite (..)
, PersistRecordBackend
, getJust
, getJustEntity
, getEntity
, belongsTo
, belongsToJust
, SafeToInsert
, insertEntity
, insertRecord
-- * PersistUnique
-- | The 'PersistUnique' type class is relevant for database backends that
-- offer uniqueness keys. Uniquenes keys allow us to perform operations like
-- 'getBy', 'deleteBy', as well as 'upsert' and 'putMany'.
--
-- All the examples present here will be explained based on these two schemas and the dataset:
--
-- = schema-1
-- This schema has single unique constraint.
--
-- #schema-persist-unique-1#
--
-- > share [mkPersist sqlSettings, mkMigrate "migrateAll"] [persistLowerCase|
-- > User
-- > name String
-- > age Int
-- > UniqueUserName name
-- > deriving Show
-- > |]
--
-- = schema-2
-- This schema has two unique constraints.
--
-- #schema-persist-unique-2#
--
-- > share [mkPersist sqlSettings, mkMigrate "migrateAll"] [persistLowerCase|
-- > User
-- > name String
-- > age Int
-- > UniqueUserName name
-- > UniqueUserAge age
-- > deriving Show
-- > |]
--
-- = dataset-1
--
-- #dataset-persist-unique-1#
--
-- > +-----+-----+-----+
-- > |id |name |age |
-- > +-----+-----+-----+
-- > |1 |SPJ |40 |
-- > +-----+-----+-----+
-- > |2 |Simon|41 |
-- > +-----+-----+-----+
, PersistUnique
, PersistUniqueRead (..)
, PersistUniqueWrite (..)
, OnlyOneUniqueKey (..)
, AtLeastOneUniqueKey (..)
, onlyOneUniqueDef
, NoUniqueKeysError
, MultipleUniqueKeysError
, getByValue
, insertBy
, insertUniqueEntity
, replaceUnique
, checkUnique
, checkUniqueUpdateable
, onlyUnique
-- * PersistQuery
-- | The 'PersistQuery' type class allows us to select lists and filter
-- database models. 'selectList' is the canonical read operation, and we
-- can write 'updateWhere' and 'deleteWhere' to modify based on filters.
, selectList
, selectKeys
, PersistQuery
, PersistQueryRead (..)
, PersistQueryWrite (..)
, selectSource
, selectKeysList
-- * PersistEntity
, PersistEntity (..)
, tabulateEntity
, SymbolToField (..)
-- * PersistField
, PersistField (..)
-- * PersistConfig
, PersistConfig (..)
, entityValues
-- * Lifting
, HasPersistBackend (..)
, withBaseBackend
, IsPersistBackend ()
, liftPersist
, BackendCompatible (..)
, withCompatibleBackend
-- * PersistCore
-- | 'PersistCore' is a type class that defines a default database
-- 'BackendKey' type. For SQL databases, this is currently an
-- auto-incrementing inteer primary key. For MongoDB, it is the default
-- ObjectID.
, PersistCore (..)
, ToBackendKey (..)
-- * JSON utilities
, keyValueEntityToJSON, keyValueEntityFromJSON
, entityIdToJSON, entityIdFromJSON
, toPersistValueJSON, fromPersistValueJSON
) where
import Database.Persist.Class.PersistConfig
import Database.Persist.Class.PersistEntity
import Database.Persist.Class.PersistField
import Database.Persist.Class.PersistQuery
import Database.Persist.Class.PersistStore
import Database.Persist.Class.PersistUnique
-- | A backwards-compatible alias for those that don't care about distinguishing between read and write queries.
-- It signifies the assumption that, by default, a backend can write as well as read.
type PersistUnique a = PersistUniqueWrite a
-- | A backwards-compatible alias for those that don't care about distinguishing between read and write queries.
-- It signifies the assumption that, by default, a backend can write as well as read.
type PersistQuery a = PersistQueryWrite a
-- | A backwards-compatible alias for those that don't care about distinguishing between read and write queries.
-- It signifies the assumption that, by default, a backend can write as well as read.
type PersistStore a = PersistStoreWrite a
|
