haskell/esqueleto
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Merge pull request #122 from rzetterberg/example-docs

Browse Source 
Adds haddock example usage of 'in_' operator
This commit is contained in:
Felipe Lessa 2016-01-01 01:23:22 -02:00
commit 99dfbc526b
1 changed files with 19 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
src/Database/Esqueleto/Internal/Language.hs
View File

@ -456,7 +456,25 @@ class (Functor query, Applicative query, Monad query) =>
-- /Since: 2.2.12/ -- /Since: 2.2.12/
justList :: expr (ValueList typ) -> expr (ValueList (Maybe typ)) justList :: expr (ValueList typ) -> expr (ValueList (Maybe typ))
-- | @IN@ operator. -- | @IN@ operator. For example if you want to select all @Person@s by a list
-- of IDs:
--
-- @
-- SELECT *
-- FROM Person
-- WHERE Person.id IN (?)
-- @
--
-- In @esqueleto@, we may write the same query above as:
--
-- @
-- select $
-- 'from' $ \\person -> do
-- 'where_' $ person '^.' PersonId `in_` 'valList' personIds
-- return person
-- @
--
-- Where @personIds@ is of type @[Key Person]@.
in_ :: PersistField typ => expr (Value typ) -> expr (ValueList typ) -> expr (Value Bool) in_ :: PersistField typ => expr (Value typ) -> expr (ValueList typ) -> expr (Value Bool)
-- | @NOT IN@ operator. -- | @NOT IN@ operator.