Database.Record.FromSql

This module defines interfaces from list of SQL type into Haskell type.

Conversion from list of SQL type into record type

Structure of RecordFromSql q a is similar to parser. While running RecordFromSql behavior is the same as parser which parse list of SQL type [q] stream.

So, RecordFromSql q is Monad and Applicative instance like parser monad. When, you have data constructor and objects like below.

  data MyRecord = MyRecord Foo Bar Baz

  foo :: RecordFromSql SqlValue Foo
  foo =  ...
  bar :: RecordFromSql SqlValue Bar
  bar =  ...
  baz :: RecordFromSql SqlValue Bar
  baz =  ...

You can get composed RecordFromSql like below.

  myRecord :: RecordFromSql SqlValue MyRecord
  myRecord =  MyRecord <$> foo <*> bar <*> baz

data RecordFromSql q a

Proof object type to convert from sql value type q list into Haskell type a.

Instances

Monad (RecordFromSql q)

Monad instance like parser Monad.

Methods

(>>=) :: RecordFromSql q a -> (a -> RecordFromSql q b) -> RecordFromSql q b

(>>) :: RecordFromSql q a -> RecordFromSql q b -> RecordFromSql q b

return :: a -> RecordFromSql q a

fail :: String -> RecordFromSql q a

Functor (RecordFromSql q)

Derived Functor instance from Monad instance

Methods

fmap :: (a -> b) -> RecordFromSql q a -> RecordFromSql q b

(<$) :: a -> RecordFromSql q b -> RecordFromSql q a

Applicative (RecordFromSql q)

Derived Applicative instance from Monad instance

Methods

pure :: a -> RecordFromSql q a

(<*>) :: RecordFromSql q (a -> b) -> RecordFromSql q a -> RecordFromSql q b

(*>) :: RecordFromSql q a -> RecordFromSql q b -> RecordFromSql q b

(<*) :: RecordFromSql q a -> RecordFromSql q b -> RecordFromSql q a

runTakeRecord

Arguments

:: RecordFromSql q a

Proof object which has capability to convert

-> [q]

list of SQL type

-> (a, [q])

Haskell type and rest of list

Run RecordFromSql proof object. Convert from list of SQL type [q] into Haskell type a and rest of list [q].

runToRecord

Arguments

:: RecordFromSql q a

Proof object which has capability to convert

-> [q]

list of SQL type

-> a

Haskell type

Run RecordFromSql proof object. Convert from list of SQL type [q] into Haskell type a.

createRecordFromSql

Arguments

:: ([q] -> (a, [q]))

Convert function body

-> RecordFromSql q a

Result proof object

Axiom of RecordFromSql for SQL type q and Haskell type a

(<&>) :: RecordFromSql q a -> RecordFromSql q b -> RecordFromSql q (a, b) infixl 4

Derivation rule of RecordFromSql proof object for Haskell tuple (,) type.

maybeRecord :: PersistableType q => RecordFromSql q a -> ColumnConstraint NotNull a -> RecordFromSql q (Maybe a)

Derivation rule of RecordFromSql proof object for Haskell Maybe type.

Inference rules of RecordFromSql conversion

class FromSql q a where

Inference rule interface for RecordFromSql proof object.

Minimal complete definition

recordFromSql

Methods

recordFromSql :: RecordFromSql q a

RecordFromSql proof object.

Instances

FromSql q ()

Inference rule of RecordFromSql proof object which can convert from empty list of SQL type [q] into Haskell unit () type.

Methods

recordFromSql :: RecordFromSql q ()

(HasColumnConstraint NotNull a, FromSql q a, PersistableType q) => FromSql q (Maybe a)

Inference rule of RecordFromSql proof object which can convert from list of SQL type [q] into Haskell Maybe type.

Methods

recordFromSql :: RecordFromSql q (Maybe a)

(FromSql q a, FromSql q b) => FromSql q (a, b)

Inference rule of RecordFromSql proof object which can convert from list of SQL type [q] into Haskell tuple (a, b) type.

Methods

recordFromSql :: RecordFromSql q (a, b)

takeRecord :: FromSql q a => [q] -> (a, [q])

Run inferred RecordFromSql proof object. Convert from list of SQL type [q] into haskell type a and rest of list [q].

toRecord :: FromSql q a => [q] -> a

Run inferred RecordFromSql proof object. Convert from list of SQL type [q] into haskell type a.

valueRecordFromSql :: (q -> a) -> RecordFromSql q a

Derivation rule of RecordFromSql proof object for value convert function.