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  1. (<=.) :: forall v typ . PersistField typ => EntityField v typ -> typ -> Filter v

    persistent-mtl Database.Persist.Sql.Shim

    Less-than or equal check.

    Examples

    selectLessEqualAge :: MonadIO m => ReaderT SqlBackend m [Entity User]
selectLessEqualAge = selectList [UserAge <=. 40 ] []
    The above query when applied on dataset-1, will produce this: 
    +-----+-----+-----+
|id   |name |age  |
+-----+-----+-----+
|1    |SPJ  |40   |
+-----+-----+-----+

  2. (=.) :: forall v typ . PersistField typ => EntityField v typ -> typ -> Update v

    persistent-mtl Database.Persist.Sql.Shim

    Assign a field a value.

    Examples

    updateAge :: MonadIO m => ReaderT SqlBackend m ()
updateAge = updateWhere [UserName ==. "SPJ" ] [UserAge =. 45]
    Similar to updateWhere which is shown in the above example you can use other functions present in the module Database.Persist.Class. Note that the first parameter of updateWhere is [Filter val] and second parameter is [Update val]. By comparing this with the type of ==. and =., you can see that they match up in the above usage. The above query when applied on dataset-1, will produce this: 
    +-----+-----+--------+
|id   |name |age     |
+-----+-----+--------+
|1    |SPJ  |40 -> 45|
+-----+-----+--------+
|2    |Simon|41      |
+-----+-----+--------+

  3. (==.) :: forall v typ . PersistField typ => EntityField v typ -> typ -> Filter v

    persistent-mtl Database.Persist.Sql.Shim

    Check for equality.

    Examples

    selectSPJ :: MonadIO m => ReaderT SqlBackend m [Entity User]
selectSPJ = selectList [UserName ==. "SPJ" ] []
    The above query when applied on dataset-1, will produce this: 
    +-----+-----+-----+
|id   |name |age  |
+-----+-----+-----+
|1    |SPJ  |40   |
+-----+-----+-----+

  4. (>.) :: forall v typ . PersistField typ => EntityField v typ -> typ -> Filter v

    persistent-mtl Database.Persist.Sql.Shim

    Greater-than check.

    Examples

    selectGreaterAge :: MonadIO m => ReaderT SqlBackend m [Entity User]
selectGreaterAge = selectList [UserAge >. 40 ] []
    The above query when applied on dataset-1, will produce this: 
    +-----+-----+-----+
|id   |name |age  |
+-----+-----+-----+
|2    |Simon|41   |
+-----+-----+-----+

  5. (>=.) :: forall v typ . PersistField typ => EntityField v typ -> typ -> Filter v

    persistent-mtl Database.Persist.Sql.Shim

    Greater-than or equal check.

    Examples

    selectGreaterEqualAge :: MonadIO m => ReaderT SqlBackend m [Entity User]
selectGreaterEqualAge = selectList [UserAge >=. 41 ] []
    The above query when applied on dataset-1, will produce this: 
    +-----+-----+-----+
|id   |name |age  |
+-----+-----+-----+
|2    |Simon|41   |
+-----+-----+-----+

  6. (||.) :: [Filter v] -> [Filter v] -> [Filter v]

    persistent-mtl Database.Persist.Sql.Shim

    The OR of two lists of filters. For example: 

    selectList
([ PersonAge >. 25
, PersonAge <. 30 ] ||.
[ PersonIncome >. 15000
, PersonIncome <. 25000 ])
[]
    will filter records where a person's age is between 25 and 30 or a person's income is between (15000 and 25000). If you are looking for an (&&.) operator to do (A AND B AND (C OR D)) you can use the (++) operator instead as there is no (&&.). For example: 
    selectList
([ PersonAge >. 25
, PersonAge <. 30 ] ++
([PersonCategory ==. 1] ||.
[PersonCategory ==. 5]))
[]
    will filter records where a person's age is between 25 and 30 and (person's category is either 1 or 5).

  7. (!=.) :: forall v typ . PersistField typ => EntityField v typ -> typ -> Filter v

    persistent-redis Database.Persist.Redis

    Non-equality check.

    Examples

    selectSimon :: MonadIO m => ReaderT SqlBackend m [Entity User]
selectSimon = selectList [UserName !=. "SPJ" ] []
    The above query when applied on dataset-1, will produce this: 
    +-----+-----+-----+
|id   |name |age  |
+-----+-----+-----+
|2    |Simon|41   |
+-----+-----+-----+

  8. (*=.) :: forall v typ . PersistField typ => EntityField v typ -> typ -> Update v

    persistent-redis Database.Persist.Redis

    Assign a field by multiplication (*=).

    Examples

    multiplyAge :: MonadIO m => ReaderT SqlBackend m ()
multiplyAge = updateWhere [UserName ==. "SPJ" ] [UserAge *=. 2]
    The above query when applied on dataset-1, will produce this: 
    +-----+-----+--------+
|id   |name |age     |
+-----+-----+--------+
|1    |SPJ  |40 -> 80|
+-----+-----+--------+
|2    |Simon|41      |
+-----+-----+--------+

  9. (+=.) :: forall v typ . PersistField typ => EntityField v typ -> typ -> Update v

    persistent-redis Database.Persist.Redis

    Assign a field by addition (+=).

    Examples

    addAge :: MonadIO m => ReaderT SqlBackend m ()
addAge = updateWhere [UserName ==. "SPJ" ] [UserAge +=. 1]
    The above query when applied on dataset-1, will produce this: 
    +-----+-----+---------+
|id   |name |age      |
+-----+-----+---------+
|1    |SPJ  |40 -> 41 |
+-----+-----+---------+
|2    |Simon|41       |
+-----+-----+---------+

  10. (-=.) :: forall v typ . PersistField typ => EntityField v typ -> typ -> Update v

    persistent-redis Database.Persist.Redis

    Assign a field by subtraction (-=).

    Examples

    subtractAge :: MonadIO m => ReaderT SqlBackend m ()
subtractAge = updateWhere [UserName ==. "SPJ" ] [UserAge -=. 1]
    The above query when applied on dataset-1, will produce this: 
    +-----+-----+---------+
|id   |name |age      |
+-----+-----+---------+
|1    |SPJ  |40 -> 39 |
+-----+-----+---------+
|2    |Simon|41       |
+-----+-----+---------+

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