| Safe Haskell | None |
|---|---|
| Language | Haskell2010 |
Database.Persist.Types
Synopsis
- data Checkmark
- data IsNullable
- data WhyNullable
- data EntityDef = EntityDef {
- entityHaskell :: !HaskellName
- entityDB :: !DBName
- entityId :: !FieldDef
- entityAttrs :: ![Attr]
- entityFields :: ![FieldDef]
- entityUniques :: ![UniqueDef]
- entityForeigns :: ![ForeignDef]
- entityDerives :: ![Text]
- entityExtra :: !(Map Text [ExtraLine])
- entitySum :: !Bool
- entityComments :: !(Maybe Text)
- entityPrimary :: EntityDef -> Maybe CompositeDef
- entityKeyFields :: EntityDef -> [FieldDef]
- keyAndEntityFields :: EntityDef -> [FieldDef]
- type ExtraLine = [Text]
- newtype HaskellName = HaskellName {}
- newtype DBName = DBName {}
- type Attr = Text
- data FieldType
- data FieldDef = FieldDef {
- fieldHaskell :: !HaskellName
- fieldDB :: !DBName
- fieldType :: !FieldType
- fieldSqlType :: !SqlType
- fieldAttrs :: ![Attr]
- fieldStrict :: !Bool
- fieldReference :: !ReferenceDef
- fieldComments :: !(Maybe Text)
- data ReferenceDef
- data EmbedEntityDef = EmbedEntityDef {}
- data EmbedFieldDef = EmbedFieldDef {}
- toEmbedEntityDef :: EntityDef -> EmbedEntityDef
- data UniqueDef = UniqueDef {
- uniqueHaskell :: !HaskellName
- uniqueDBName :: !DBName
- uniqueFields :: ![(HaskellName, DBName)]
- uniqueAttrs :: ![Attr]
- data CompositeDef = CompositeDef {
- compositeFields :: ![FieldDef]
- compositeAttrs :: ![Attr]
- type ForeignFieldDef = (HaskellName, DBName)
- data ForeignDef = ForeignDef {}
- data PersistException
- data PersistValue
- = PersistText Text
- | PersistByteString ByteString
- | PersistInt64 Int64
- | PersistDouble Double
- | PersistRational Rational
- | PersistBool Bool
- | PersistDay Day
- | PersistTimeOfDay TimeOfDay
- | PersistUTCTime UTCTime
- | PersistNull
- | PersistList [PersistValue]
- | PersistMap [(Text, PersistValue)]
- | PersistObjectId ByteString
- | PersistArray [PersistValue]
- | PersistDbSpecific ByteString
- fromPersistValueText :: PersistValue -> Either Text Text
- data SqlType
- data PersistFilter
- data UpdateException
- data OnlyUniqueException = OnlyUniqueException String
- data PersistUpdate
- data SomePersistField = PersistField a => SomePersistField a
- data Update record
- = PersistField typ => Update {
- updateField :: EntityField record typ
- updateValue :: typ
- updateUpdate :: PersistUpdate
- | BackendUpdate (BackendSpecificUpdate (PersistEntityBackend record) record)
- = PersistField typ => Update {
- type family BackendSpecificUpdate backend record
- data SelectOpt record
- = Asc (EntityField record typ)
- | Desc (EntityField record typ)
- | OffsetBy Int
- | LimitTo Int
- data Filter record
- = PersistField typ => Filter {
- filterField :: EntityField record typ
- filterValue :: FilterValue typ
- filterFilter :: PersistFilter
- | FilterAnd [Filter record]
- | FilterOr [Filter record]
- | BackendFilter (BackendSpecificFilter (PersistEntityBackend record) record)
- = PersistField typ => Filter {
- data FilterValue typ where
- FilterValue :: typ -> FilterValue typ
- FilterValues :: [typ] -> FilterValue typ
- UnsafeValue :: forall a typ. PersistField a => a -> FilterValue typ
- type family BackendSpecificFilter backend record
- data family Key record
- data Entity record = Entity {}
Documentation
A Checkmark should be used as a field type whenever a
uniqueness constraint should guarantee that a certain kind of
record may appear at most once, but other kinds of records may
appear any number of times.
NOTE: You need to mark any Checkmark fields as nullable
(see the following example).
For example, suppose there's a Location entity that
represents where a user has lived:
Location
user UserId
name Text
current Checkmark nullable
UniqueLocation user current
The UniqueLocation constraint allows any number of
Inactive Locations to be current. However, there may be
at most one current Location per user (i.e., either zero
or one per user).
This data type works because of the way that SQL treats
NULLable fields within uniqueness constraints. The SQL
standard says that NULL values should be considered
different, so we represent Inactive as SQL NULL, thus
allowing any number of Inactive records. On the other hand,
we represent Active as TRUE, so the uniqueness constraint
will disallow more than one Active record.
Note: There may be DBMSs that do not respect the SQL
standard's treatment of NULL values on uniqueness
constraints, please check if this data type works before
relying on it.
The SQL BOOLEAN type is used because it's the smallest data
type available. Note that we never use FALSE, just TRUE
and NULL. Provides the same behavior Maybe () would if
() was a valid PersistField.
Constructors
| Active | When used on a uniqueness constraint, there
may be at most one |
| Inactive | When used on a uniqueness constraint, there
may be any number of |
Instances
data IsNullable Source #
Constructors
| Nullable !WhyNullable | |
| NotNullable |
Instances
| Eq IsNullable Source # | |
Defined in Database.Persist.Types.Base | |
| Show IsNullable Source # | |
Defined in Database.Persist.Types.Base Methods showsPrec :: Int -> IsNullable -> ShowS # show :: IsNullable -> String # showList :: [IsNullable] -> ShowS # | |
data WhyNullable Source #
The reason why a field is nullable is very important. A
field that is nullable because of a Maybe tag will have its
type changed from A to Maybe A. OTOH, a field that is
nullable because of a nullable tag will remain with the same
type.
Constructors
| ByMaybeAttr | |
| ByNullableAttr |
Instances
| Eq WhyNullable Source # | |
Defined in Database.Persist.Types.Base | |
| Show WhyNullable Source # | |
Defined in Database.Persist.Types.Base Methods showsPrec :: Int -> WhyNullable -> ShowS # show :: WhyNullable -> String # showList :: [WhyNullable] -> ShowS # | |
An EntityDef represents the information that persistent knows
about an Entity. It uses this information to generate the Haskell
datatype, the SQL migrations, and other relevant conversions.
Constructors
| EntityDef | |
Fields
| |
Instances
| Eq EntityDef Source # | |
| Ord EntityDef Source # | |
| Read EntityDef Source # | |
| Show EntityDef Source # | |
entityKeyFields :: EntityDef -> [FieldDef] Source #
keyAndEntityFields :: EntityDef -> [FieldDef] Source #
newtype HaskellName Source #
Constructors
| HaskellName | |
Fields | |
Instances
| Eq HaskellName Source # | |
Defined in Database.Persist.Types.Base | |
| Ord HaskellName Source # | |
Defined in Database.Persist.Types.Base Methods compare :: HaskellName -> HaskellName -> Ordering # (<) :: HaskellName -> HaskellName -> Bool # (<=) :: HaskellName -> HaskellName -> Bool # (>) :: HaskellName -> HaskellName -> Bool # (>=) :: HaskellName -> HaskellName -> Bool # max :: HaskellName -> HaskellName -> HaskellName # min :: HaskellName -> HaskellName -> HaskellName # | |
| Read HaskellName Source # | |
Defined in Database.Persist.Types.Base Methods readsPrec :: Int -> ReadS HaskellName # readList :: ReadS [HaskellName] # readPrec :: ReadPrec HaskellName # readListPrec :: ReadPrec [HaskellName] # | |
| Show HaskellName Source # | |
Defined in Database.Persist.Types.Base Methods showsPrec :: Int -> HaskellName -> ShowS # show :: HaskellName -> String # showList :: [HaskellName] -> ShowS # | |
Constructors
| FTTypeCon (Maybe Text) Text | Optional module and name. |
| FTApp FieldType FieldType | |
| FTList FieldType |
Instances
| Eq FieldType Source # | |
| Ord FieldType Source # | |
| Read FieldType Source # | |
| Show FieldType Source # | |
A FieldDef represents the inormation that persistent knows about
a field of a datatype. This includes information used to parse the field
out of the database and what the field corresponds to.
Constructors
| FieldDef | |
Fields
| |
data ReferenceDef Source #
There are 3 kinds of references 1) composite (to fields that exist in the record) 2) single field 3) embedded
Constructors
| NoReference | |
| ForeignRef !HaskellName !FieldType | A ForeignRef has a late binding to the EntityDef it references via HaskellName and has the Haskell type of the foreign key in the form of FieldType |
| EmbedRef EmbedEntityDef | |
| CompositeRef CompositeDef | |
| SelfReference | A SelfReference stops an immediate cycle which causes non-termination at compile-time (issue #311). |
Instances
| Eq ReferenceDef Source # | |
Defined in Database.Persist.Types.Base | |
| Ord ReferenceDef Source # | |
Defined in Database.Persist.Types.Base Methods compare :: ReferenceDef -> ReferenceDef -> Ordering # (<) :: ReferenceDef -> ReferenceDef -> Bool # (<=) :: ReferenceDef -> ReferenceDef -> Bool # (>) :: ReferenceDef -> ReferenceDef -> Bool # (>=) :: ReferenceDef -> ReferenceDef -> Bool # max :: ReferenceDef -> ReferenceDef -> ReferenceDef # min :: ReferenceDef -> ReferenceDef -> ReferenceDef # | |
| Read ReferenceDef Source # | |
Defined in Database.Persist.Types.Base Methods readsPrec :: Int -> ReadS ReferenceDef # readList :: ReadS [ReferenceDef] # | |
| Show ReferenceDef Source # | |
Defined in Database.Persist.Types.Base Methods showsPrec :: Int -> ReferenceDef -> ShowS # show :: ReferenceDef -> String # showList :: [ReferenceDef] -> ShowS # | |
data EmbedEntityDef Source #
An EmbedEntityDef is the same as an EntityDef But it is only used for fieldReference so it only has data needed for embedding
Constructors
| EmbedEntityDef | |
Fields | |
Instances
| Eq EmbedEntityDef Source # | |
Defined in Database.Persist.Types.Base Methods (==) :: EmbedEntityDef -> EmbedEntityDef -> Bool # (/=) :: EmbedEntityDef -> EmbedEntityDef -> Bool # | |
| Ord EmbedEntityDef Source # | |
Defined in Database.Persist.Types.Base Methods compare :: EmbedEntityDef -> EmbedEntityDef -> Ordering # (<) :: EmbedEntityDef -> EmbedEntityDef -> Bool # (<=) :: EmbedEntityDef -> EmbedEntityDef -> Bool # (>) :: EmbedEntityDef -> EmbedEntityDef -> Bool # (>=) :: EmbedEntityDef -> EmbedEntityDef -> Bool # max :: EmbedEntityDef -> EmbedEntityDef -> EmbedEntityDef # min :: EmbedEntityDef -> EmbedEntityDef -> EmbedEntityDef # | |
| Read EmbedEntityDef Source # | |
Defined in Database.Persist.Types.Base Methods readsPrec :: Int -> ReadS EmbedEntityDef # readList :: ReadS [EmbedEntityDef] # | |
| Show EmbedEntityDef Source # | |
Defined in Database.Persist.Types.Base Methods showsPrec :: Int -> EmbedEntityDef -> ShowS # show :: EmbedEntityDef -> String # showList :: [EmbedEntityDef] -> ShowS # | |
data EmbedFieldDef Source #
An EmbedFieldDef is the same as a FieldDef But it is only used for embeddedFields so it only has data needed for embedding
Constructors
| EmbedFieldDef | |
Fields
| |
Instances
| Eq EmbedFieldDef Source # | |
Defined in Database.Persist.Types.Base Methods (==) :: EmbedFieldDef -> EmbedFieldDef -> Bool # (/=) :: EmbedFieldDef -> EmbedFieldDef -> Bool # | |
| Ord EmbedFieldDef Source # | |
Defined in Database.Persist.Types.Base Methods compare :: EmbedFieldDef -> EmbedFieldDef -> Ordering # (<) :: EmbedFieldDef -> EmbedFieldDef -> Bool # (<=) :: EmbedFieldDef -> EmbedFieldDef -> Bool # (>) :: EmbedFieldDef -> EmbedFieldDef -> Bool # (>=) :: EmbedFieldDef -> EmbedFieldDef -> Bool # max :: EmbedFieldDef -> EmbedFieldDef -> EmbedFieldDef # min :: EmbedFieldDef -> EmbedFieldDef -> EmbedFieldDef # | |
| Read EmbedFieldDef Source # | |
Defined in Database.Persist.Types.Base Methods readsPrec :: Int -> ReadS EmbedFieldDef # readList :: ReadS [EmbedFieldDef] # | |
| Show EmbedFieldDef Source # | |
Defined in Database.Persist.Types.Base Methods showsPrec :: Int -> EmbedFieldDef -> ShowS # show :: EmbedFieldDef -> String # showList :: [EmbedFieldDef] -> ShowS # | |
Constructors
| UniqueDef | |
Fields
| |
Instances
| Eq UniqueDef Source # | |
| Ord UniqueDef Source # | |
| Read UniqueDef Source # | |
| Show UniqueDef Source # | |
data CompositeDef Source #
Constructors
| CompositeDef | |
Fields
| |
Instances
| Eq CompositeDef Source # | |
Defined in Database.Persist.Types.Base | |
| Ord CompositeDef Source # | |
Defined in Database.Persist.Types.Base Methods compare :: CompositeDef -> CompositeDef -> Ordering # (<) :: CompositeDef -> CompositeDef -> Bool # (<=) :: CompositeDef -> CompositeDef -> Bool # (>) :: CompositeDef -> CompositeDef -> Bool # (>=) :: CompositeDef -> CompositeDef -> Bool # max :: CompositeDef -> CompositeDef -> CompositeDef # min :: CompositeDef -> CompositeDef -> CompositeDef # | |
| Read CompositeDef Source # | |
Defined in Database.Persist.Types.Base Methods readsPrec :: Int -> ReadS CompositeDef # readList :: ReadS [CompositeDef] # | |
| Show CompositeDef Source # | |
Defined in Database.Persist.Types.Base Methods showsPrec :: Int -> CompositeDef -> ShowS # show :: CompositeDef -> String # showList :: [CompositeDef] -> ShowS # | |
type ForeignFieldDef = (HaskellName, DBName) Source #
Used instead of FieldDef to generate a smaller amount of code
data ForeignDef Source #
Constructors
| ForeignDef | |
Fields | |
Instances
| Eq ForeignDef Source # | |
Defined in Database.Persist.Types.Base | |
| Ord ForeignDef Source # | |
Defined in Database.Persist.Types.Base Methods compare :: ForeignDef -> ForeignDef -> Ordering # (<) :: ForeignDef -> ForeignDef -> Bool # (<=) :: ForeignDef -> ForeignDef -> Bool # (>) :: ForeignDef -> ForeignDef -> Bool # (>=) :: ForeignDef -> ForeignDef -> Bool # max :: ForeignDef -> ForeignDef -> ForeignDef # min :: ForeignDef -> ForeignDef -> ForeignDef # | |
| Read ForeignDef Source # | |
Defined in Database.Persist.Types.Base Methods readsPrec :: Int -> ReadS ForeignDef # readList :: ReadS [ForeignDef] # readPrec :: ReadPrec ForeignDef # readListPrec :: ReadPrec [ForeignDef] # | |
| Show ForeignDef Source # | |
Defined in Database.Persist.Types.Base Methods showsPrec :: Int -> ForeignDef -> ShowS # show :: ForeignDef -> String # showList :: [ForeignDef] -> ShowS # | |
data PersistException Source #
Constructors
| PersistError Text | Generic Exception |
| PersistMarshalError Text | |
| PersistInvalidField Text | |
| PersistForeignConstraintUnmet Text | |
| PersistMongoDBError Text | |
| PersistMongoDBUnsupported Text |
Instances
| Show PersistException Source # | |
Defined in Database.Persist.Types.Base Methods showsPrec :: Int -> PersistException -> ShowS # show :: PersistException -> String # showList :: [PersistException] -> ShowS # | |
| Exception PersistException Source # | |
Defined in Database.Persist.Types.Base Methods toException :: PersistException -> SomeException # | |
| Error PersistException Source # | |
Defined in Database.Persist.Types.Base | |
data PersistValue Source #
A raw value which can be stored in any backend and can be marshalled to
and from a PersistField.
Constructors
| PersistText Text | |
| PersistByteString ByteString | |
| PersistInt64 Int64 | |
| PersistDouble Double | |
| PersistRational Rational | |
| PersistBool Bool | |
| PersistDay Day | |
| PersistTimeOfDay TimeOfDay | |
| PersistUTCTime UTCTime | |
| PersistNull | |
| PersistList [PersistValue] | |
| PersistMap [(Text, PersistValue)] | |
| PersistObjectId ByteString | Intended especially for MongoDB backend |
| PersistArray [PersistValue] | Intended especially for PostgreSQL backend for text arrays |
| PersistDbSpecific ByteString | Using data Geo = Geo ByteString
instance PersistField Geo where
toPersistValue (Geo t) = PersistDbSpecific t
fromPersistValue (PersistDbSpecific t) = Right $ Geo $ Data.ByteString.concat ["'", t, "'"]
fromPersistValue _ = Left "Geo values must be converted from PersistDbSpecific"
instance PersistFieldSql Geo where
sqlType _ = SqlOther "GEOGRAPHY(POINT,4326)"
toPoint :: Double -> Double -> Geo
toPoint lat lon = Geo $ Data.ByteString.concat ["'POINT(", ps $ lon, " ", ps $ lat, ")'"]
where ps = Data.Text.pack . show
If Foo has a geography field, we can then perform insertions like the following: insert $ Foo (toPoint 44 44) |
Instances
A SQL data type. Naming attempts to reflect the underlying Haskell datatypes, eg SqlString instead of SqlVarchar. Different SQL databases may have different translations for these types.
Constructors
| SqlString | |
| SqlInt32 | |
| SqlInt64 | |
| SqlReal | |
| SqlNumeric Word32 Word32 | |
| SqlBool | |
| SqlDay | |
| SqlTime | |
| SqlDayTime | Always uses UTC timezone |
| SqlBlob | |
| SqlOther Text | a backend-specific name |
data PersistFilter Source #
Instances
| Read PersistFilter Source # | |
Defined in Database.Persist.Types.Base Methods readsPrec :: Int -> ReadS PersistFilter # readList :: ReadS [PersistFilter] # | |
| Show PersistFilter Source # | |
Defined in Database.Persist.Types.Base Methods showsPrec :: Int -> PersistFilter -> ShowS # show :: PersistFilter -> String # showList :: [PersistFilter] -> ShowS # | |
data UpdateException Source #
Constructors
| KeyNotFound String | |
| UpsertError String |
Instances
| Show UpdateException Source # | |
Defined in Database.Persist.Types.Base Methods showsPrec :: Int -> UpdateException -> ShowS # show :: UpdateException -> String # showList :: [UpdateException] -> ShowS # | |
| Exception UpdateException Source # | |
Defined in Database.Persist.Types.Base Methods toException :: UpdateException -> SomeException # | |
data OnlyUniqueException Source #
Constructors
| OnlyUniqueException String |
Instances
| Show OnlyUniqueException Source # | |
Defined in Database.Persist.Types.Base Methods showsPrec :: Int -> OnlyUniqueException -> ShowS # show :: OnlyUniqueException -> String # showList :: [OnlyUniqueException] -> ShowS # | |
| Exception OnlyUniqueException Source # | |
Defined in Database.Persist.Types.Base Methods toException :: OnlyUniqueException -> SomeException # fromException :: SomeException -> Maybe OnlyUniqueException # | |
data PersistUpdate Source #
Instances
| Read PersistUpdate Source # | |
Defined in Database.Persist.Types.Base Methods readsPrec :: Int -> ReadS PersistUpdate # readList :: ReadS [PersistUpdate] # | |
| Show PersistUpdate Source # | |
Defined in Database.Persist.Types.Base Methods showsPrec :: Int -> PersistUpdate -> ShowS # show :: PersistUpdate -> String # showList :: [PersistUpdate] -> ShowS # | |
data SomePersistField Source #
Constructors
| PersistField a => SomePersistField a |
Instances
| PersistField SomePersistField Source # | |
Defined in Database.Persist.Class.PersistField Methods toPersistValue :: SomePersistField -> PersistValue Source # fromPersistValue :: PersistValue -> Either Text SomePersistField Source # | |
Updating a database entity.
Persistent users use combinators to create these.
Constructors
| PersistField typ => Update | |
Fields
| |
| BackendUpdate (BackendSpecificUpdate (PersistEntityBackend record) record) | |
type family BackendSpecificUpdate backend record Source #
data SelectOpt record Source #
Query options.
Persistent users use these directly.
Constructors
| Asc (EntityField record typ) | |
| Desc (EntityField record typ) | |
| OffsetBy Int | |
| LimitTo Int |
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.
Persistent users use combinators to create these.
Note that it's important to be careful about the PersistFilter that
you are using, if you use this directly. For example, using the In
PersistFilter requires that you have an array- or list-shaped
EntityField. It is possible to construct values using this that will
create malformed runtime values.
Constructors
| PersistField typ => Filter | |
Fields
| |
| FilterAnd [Filter record] | convenient for internal use, not needed for the API |
| FilterOr [Filter record] | |
| BackendFilter (BackendSpecificFilter (PersistEntityBackend record) record) | |
data FilterValue typ where Source #
Value to filter with. Highly dependant on the type of filter used.
Since: 2.10.0
Constructors
| FilterValue :: typ -> FilterValue typ | |
| FilterValues :: [typ] -> FilterValue typ | |
| UnsafeValue :: forall a typ. PersistField a => a -> FilterValue typ |
type family BackendSpecificFilter backend record Source #
data family Key record Source #
By default, a backend will automatically generate the key Instead you can specify a Primary key made up of unique values.
Instances
| (PersistEntity a, PersistEntityBackend a ~ backend, IsPersistBackend backend) => RawSql (Key a) Source # | |
Defined in Database.Persist.Sql.Class Methods rawSqlCols :: (DBName -> Text) -> Key a -> (Int, [Text]) Source # rawSqlColCountReason :: Key a -> String Source # rawSqlProcessRow :: [PersistValue] -> Either Text (Key a) Source # | |
Datatype that represents an entity, with both its Key and
its Haskell record representation.
When using a SQL-based backend (such as SQLite or
PostgreSQL), an Entity may take any number of columns
depending on how many fields it has. In order to reconstruct
your entity on the Haskell side, persistent needs all of
your entity columns and in the right order. Note that you
don't need to worry about this when using persistent's API
since everything is handled correctly behind the scenes.
However, if you want to issue a raw SQL command that returns
an Entity, then you have to be careful with the column
order. While you could use SELECT Entity.* WHERE ... and
that would work most of the time, there are times when the
order of the columns on your database is different from the
order that persistent expects (for example, if you add a new
field in the middle of you entity definition and then use the
migration code -- persistent will expect the column to be in
the middle, but your DBMS will put it as the last column).
So, instead of using a query like the one above, you may use
rawSql (from the
Database.Persist.GenericSql module) with its /entity
selection placeholder/ (a double question mark ??). Using
rawSql the query above must be written as SELECT ?? WHERE
... Then rawSql will replace ?? with the list of all
columns that we need from your entity in the right order. If
your query returns two entities (i.e. (Entity backend a,
Entity backend b)), then you must you use SELECT ??, ??
WHERE ..., and so on.