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1. class (PersistUniqueRead backend, PersistStoreWrite backend) => PersistUniqueWrite backend

   esqueleto	Database.Esqueleto.Legacy

   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.

2. newtype PersistUnsafeMigrationException

   esqueleto	Database.Esqueleto.Legacy

   An exception indicating that Persistent refused to run some unsafe migrations. Contains a list of pairs where the Bool tracks whether the migration was unsafe (True means unsafe), and the Sql is the sql statement for the migration.

3. PersistUnsafeMigrationException :: [(Bool, Sql)] -> PersistUnsafeMigrationException

   esqueleto	Database.Esqueleto.Legacy

   No documentation available.

4. data PersistUpdate

   esqueleto	Database.Esqueleto.Legacy

   No documentation available.

5. data PersistValue

   esqueleto	Database.Esqueleto.Legacy

   A raw value which can be stored in any backend and can be marshalled to and from a PersistField.

6. data PersistentSqlException

   esqueleto	Database.Esqueleto.Legacy

   No documentation available.

7. type PersistableRecordWidth a = ProductConst Sum Int a

   persistable-record	Database.Record

   Proposition to specify width of Haskell type a. The width is length of database value list which is converted from Haskell type a.

8. data PersistableSqlType q

   persistable-record	Database.Record

   Proposition to specify type q is database value type, contains null value

9. class Eq q => PersistableType q

   persistable-record	Database.Record

   Interface of derivation rule for PersistableSqlType.

10. class PersistableWidth a

    persistable-record	Database.Record

    PersistableWidth a is implicit rule to derive PersistableRecordWidth a width proposition for type a. Generic programming (https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/glasgow_exts.html#generic-programming) with default signature is available for PersistableWidth class, so you can make instance like below:

    {-# LANGUAGE DeriveGeneric #-}
    import GHC.Generics (Generic)
    --
    data Foo = Foo { ... } deriving Generic
    instance PersistableWidth Foo
    

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