Database.Record.Persistable

This module defines interfaces between Haskell type and list of SQL type.

Specify SQL type

data PersistableSqlType q

Proof object to specify type q is SQL type

runPersistableNullValue :: PersistableSqlType q -> q

Null value of SQL type q.

unsafePersistableSqlTypeFromNull

Arguments

:: q

SQL null value of SQL type q

-> PersistableSqlType q

Result proof object

Unsafely generate PersistableSqlType proof object from specified SQL null value which type is q.

Specify record width

data PersistableRecordWidth a

Proof object to specify width of Haskell type a when converting to SQL type list.

runPersistableRecordWidth :: PersistableRecordWidth a -> Int

Get width Int value of record type a.

unsafePersistableRecordWidth

Arguments

:: Int

Specify width of Haskell type a

-> PersistableRecordWidth a

Result proof object

Unsafely generate PersistableRecordWidth proof object from specified width of Haskell type a.

unsafeValueWidth :: PersistableRecordWidth a

Unsafely generate PersistableRecordWidth proof object for Haskell type a which is single column type.

(<&>) :: PersistableRecordWidth a -> PersistableRecordWidth b -> PersistableRecordWidth (a, b)

Derivation rule of PersistableRecordWidth for tuple (,) type.

maybeWidth :: PersistableRecordWidth a -> PersistableRecordWidth (Maybe a)

Derivation rule of PersistableRecordWidth from from Haskell type a into for Haskell type Maybe a.

Inference rules for proof objects

class Eq q => PersistableType q where

Interface of inference rule for PersistableSqlType proof object

Minimal complete definition

persistableType

Methods

persistableType :: PersistableSqlType q

sqlNullValue :: PersistableType q => q

Inferred Null value of SQL type.

class PersistableWidth a where

Interface of inference rule for PersistableRecordWidth proof object

Minimal complete definition

persistableWidth

Methods

persistableWidth :: PersistableRecordWidth a

Instances

PersistableWidth ()

Inference rule of PersistableRecordWidth for Haskell unit () type. Derive from axiom.

Methods

persistableWidth :: PersistableRecordWidth ()

PersistableWidth a => PersistableWidth (Maybe a)

Inference rule of PersistableRecordWidth proof object for Maybe type.

Methods

persistableWidth :: PersistableRecordWidth (Maybe a)

(PersistableWidth a, PersistableWidth b) => PersistableWidth (a, b)

Inference rule of PersistableRecordWidth proof object for tuple (a, b) type.

Methods

persistableWidth :: PersistableRecordWidth (a, b)

derivedWidth :: PersistableWidth a => (PersistableRecordWidth a, Int)

Pass type parameter and inferred width value.