persistent-0.7.0: Type-safe, multi-backend data serialization.

Database.Persist.Query

Contents

Synopsis

Documentation

class PersistStore b m => PersistQuery b m whereSource

Methods

update :: PersistEntity val => Key b val -> [Update val] -> b m ()Source

Update individual fields on a specific record.

updateWhere :: PersistEntity val => [Filter val] -> [Update val] -> b m ()Source

Update individual fields on any record matching the given criterion.

deleteWhere :: PersistEntity val => [Filter val] -> b m ()Source

Delete all records matching the given criterion.

selectSource :: PersistEntity val => [Filter val] -> [SelectOpt val] -> Source (b m) (Entity b val)Source

Get all records matching the given criterion in the specified order. Returns also the identifiers.

selectFirst :: PersistEntity val => [Filter val] -> [SelectOpt val] -> b m (Maybe (Entity b val))Source

get just the first record for the criterion

selectKeys :: PersistEntity val => [Filter val] -> Source (b m) (Key b val)Source

Get the Keys of all records matching the given criterion.

count :: PersistEntity val => [Filter val] -> b m IntSource

The total number of records fulfilling the given criterion.

selectList :: (PersistEntity val, PersistQuery b m) => [Filter val] -> [SelectOpt val] -> b m [Entity b val]Source

Call select but return the result as a list.

data SelectOpt v Source

Constructors

forall typ . Asc (EntityField v typ) 
forall typ . Desc (EntityField v typ) 
OffsetBy Int 
LimitTo Int 

data Filter v Source

Filters which are available for select, updateWhere and deleteWhere. Each filter constructor specifies the field being filtered on, the type of comparison applied (equals, not equals, etc) and the argument for the comparison.

Constructors

forall typ . PersistField typ => Filter 
FilterAnd [Filter v]

convenient for internal use, not needed for the API

FilterOr [Filter v] 

query combinators

(=.), (/=.), (*=.), (-=.), (+=.) :: forall v typ. PersistField typ => EntityField v typ -> typ -> Update vSource

(==.), (>=.), (>.), (<=.), (<.), (!=.) :: forall v typ. PersistField typ => EntityField v typ -> typ -> Filter vSource

assign a field a value

assign a field by addition (+=)

assign a field by subtraction (-=)

assign a field by multiplication (*=)

assign a field by division (/=)

(<-.), (/<-.) :: forall v typ. PersistField typ => EntityField v typ -> [typ] -> Filter vSource

(||.) :: forall v. [Filter v] -> [Filter v] -> [Filter v]Source

In

NotIn