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  1. getJust :: forall record backend m . (PersistStoreRead backend, PersistRecordBackend record backend, MonadIO m) => Key record -> ReaderT backend m record

    persistent Database.Persist.Class

    Same as get, but for a non-null (not Maybe) foreign key. Unsafe unless your database is enforcing that the foreign key is valid.

    Example usage

    With schema-1 and dataset-1, 
    getJustSpj :: MonadIO m => ReaderT SqlBackend m User
getJustSpj = getJust spjId

    spj <- getJust spjId
    The above query when applied on dataset-1, will get this record: 
    +----+------+-----+
| id | name | age |
+----+------+-----+
|  1 | SPJ  |  40 |
+----+------+-----+

    getJustUnknown :: MonadIO m => ReaderT SqlBackend m User
getJustUnknown = getJust unknownId
    mrx <- getJustUnknown This just throws an error.

  2. getJustEntity :: forall record backend m . (PersistEntityBackend record ~ BaseBackend backend, MonadIO m, PersistEntity record, PersistStoreRead backend) => Key record -> ReaderT backend m (Entity record)

    persistent Database.Persist.Class

    Same as getJust, but returns an Entity instead of just the record.

    Example usage

    With schema-1 and dataset-1, 
    getJustEntitySpj :: MonadIO m => ReaderT SqlBackend m (Entity User)
getJustEntitySpj = getJustEntity spjId

    spjEnt <- getJustEntitySpj
    The above query when applied on dataset-1, will get this entity: 
    +----+------+-----+
| id | name | age |
+----+------+-----+
|  1 | SPJ  |  40 |
+----+------+-----+

  3. getMany :: forall record m . (PersistStoreRead backend, MonadIO m, PersistRecordBackend record backend) => [Key record] -> ReaderT backend m (Map (Key record) record)

    persistent Database.Persist.Class

    Get many records by their respective identifiers, if available.

    Example usage

    With schema-1 and dataset-1: 
    getUsers :: MonadIO m => ReaderT SqlBackend m (Map (Key User) User)
getUsers = getMany allkeys

    musers <- getUsers
    The above query when applied on dataset-1, will get these records: 
    +----+-------+-----+
| id | name  | age |
+----+-------+-----+
|  1 | SPJ   |  40 |
+----+-------+-----+
|  2 | Simon |  41 |
+----+-------+-----+

  4. getPersistMap :: PersistValue -> Either Text [(Text, PersistValue)]

    persistent Database.Persist.Class.PersistField

    FIXME Add documentation to that.

  5. getEntity :: forall e backend m . (PersistStoreRead backend, PersistRecordBackend e backend, MonadIO m) => Key e -> ReaderT backend m (Maybe (Entity e))

    persistent Database.Persist.Class.PersistStore

    Like get, but returns the complete Entity.

    Example usage

    With schema-1 and dataset-1, 
    getSpjEntity :: MonadIO m => ReaderT SqlBackend m (Maybe (Entity User))
getSpjEntity = getEntity spjId

    mSpjEnt <- getSpjEntity
    The above query when applied on dataset-1, will get this entity: 
    +----+------+-----+
| id | name | age |
+----+------+-----+
|  1 | SPJ  |  40 |
+----+------+-----+

  6. getJust :: forall record backend m . (PersistStoreRead backend, PersistRecordBackend record backend, MonadIO m) => Key record -> ReaderT backend m record

    persistent Database.Persist.Class.PersistStore

    Same as get, but for a non-null (not Maybe) foreign key. Unsafe unless your database is enforcing that the foreign key is valid.

    Example usage

    With schema-1 and dataset-1, 
    getJustSpj :: MonadIO m => ReaderT SqlBackend m User
getJustSpj = getJust spjId

    spj <- getJust spjId
    The above query when applied on dataset-1, will get this record: 
    +----+------+-----+
| id | name | age |
+----+------+-----+
|  1 | SPJ  |  40 |
+----+------+-----+

    getJustUnknown :: MonadIO m => ReaderT SqlBackend m User
getJustUnknown = getJust unknownId
    mrx <- getJustUnknown This just throws an error.

  7. getJustEntity :: forall record backend m . (PersistEntityBackend record ~ BaseBackend backend, MonadIO m, PersistEntity record, PersistStoreRead backend) => Key record -> ReaderT backend m (Entity record)

    persistent Database.Persist.Class.PersistStore

    Same as getJust, but returns an Entity instead of just the record.

    Example usage

    With schema-1 and dataset-1, 
    getJustEntitySpj :: MonadIO m => ReaderT SqlBackend m (Entity User)
getJustEntitySpj = getJustEntity spjId

    spjEnt <- getJustEntitySpj
    The above query when applied on dataset-1, will get this entity: 
    +----+------+-----+
| id | name | age |
+----+------+-----+
|  1 | SPJ  |  40 |
+----+------+-----+

  8. getMany :: forall record m . (PersistStoreRead backend, MonadIO m, PersistRecordBackend record backend) => [Key record] -> ReaderT backend m (Map (Key record) record)

    persistent Database.Persist.Class.PersistStore

    Get many records by their respective identifiers, if available.

    Example usage

    With schema-1 and dataset-1: 
    getUsers :: MonadIO m => ReaderT SqlBackend m (Map (Key User) User)
getUsers = getMany allkeys

    musers <- getUsers
    The above query when applied on dataset-1, will get these records: 
    +----+-------+-----+
| id | name  | age |
+----+-------+-----+
|  1 | SPJ   |  40 |
+----+-------+-----+
|  2 | Simon |  41 |
+----+-------+-----+

  9. getBy :: forall record m . (PersistUniqueRead backend, MonadIO m, PersistRecordBackend record backend) => Unique record -> ReaderT backend m (Maybe (Entity record))

    persistent Database.Persist.Class.PersistUnique

    Get a record by unique key, if available. Returns also the identifier.

    Example usage

    With schema-1 and dataset-1: 
    getBySpjName :: MonadIO m  => ReaderT SqlBackend m (Maybe (Entity User))
getBySpjName = getBy $ UniqueUserName "SPJ"

    mSpjEnt <- getBySpjName
    The above query when applied on dataset-1, will get this entity: 
    +----+------+-----+
| id | name | age |
+----+------+-----+
|  1 | SPJ  |  40 |
+----+------+-----+

  10. getByValue :: forall record m backend . (MonadIO m, PersistUniqueRead backend, PersistRecordBackend record backend, AtLeastOneUniqueKey record) => record -> ReaderT backend m (Maybe (Entity record))

    persistent Database.Persist.Class.PersistUnique

    A modification of getBy, which takes the PersistEntity itself instead of a Unique record. Returns a record matching one of the unique keys. This function makes the most sense on entities with a single Unique constructor.

    Example usage

    With schema-1 and dataset-1, getBySpjValue :: MonadIO m => ReaderT SqlBackend m (Maybe (Entity User)) getBySpjValue = getByValue $ User SPJ 999 
    mSpjEnt <- getBySpjValue
    The above query when applied on dataset-1, will get this record: 
    +----+------+-----+
| id | name | age |
+----+------+-----+
|  1 | SPJ  |  40 |
+----+------+-----+

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