| Portability | non portable |
|---|---|
| Stability | experimental |
| Maintainer | haskelldb-users@lists.sourceforge.net |
Database.HaskellDB.PrimQuery
Description
PrimQuery defines the datatype of relational expressions
(PrimQuery) and some useful functions on PrimQuery's
- type TableName = String
- type Attribute = String
- type Scheme = [Attribute]
- type Assoc = [(Attribute, PrimExpr)]
- type Name = String
- data PrimQuery
- data RelOp
- = Times
- | Union
- | Intersect
- | Divide
- | Difference
- data SpecialOp
- data PrimExpr
- data OrderExpr = OrderExpr OrderOp PrimExpr
- data BinOp
- data UnOp
- = OpNot
- | OpIsNull
- | OpIsNotNull
- | OpLength
- | UnOpOther String
- data OrderOp
- data AggrOp
- = AggrCount
- | AggrSum
- | AggrAvg
- | AggrMin
- | AggrMax
- | AggrStdDev
- | AggrStdDevP
- | AggrVar
- | AggrVarP
- | AggrOther String
- data Literal
- = NullLit
- | DefaultLit
- | BoolLit Bool
- | StringLit String
- | IntegerLit Integer
- | DoubleLit Double
- | DateLit CalendarTime
- | OtherLit String
- extend :: Assoc -> PrimQuery -> PrimQuery
- times :: PrimQuery -> PrimQuery -> PrimQuery
- attributes :: PrimQuery -> Scheme
- attrInExpr :: PrimExpr -> Scheme
- attrInOrder :: [OrderExpr] -> Scheme
- substAttr :: Assoc -> PrimExpr -> PrimExpr
- isAggregate :: PrimExpr -> Bool
- isConstant :: PrimExpr -> Bool
- foldPrimQuery :: (t, TableName -> Scheme -> t, Assoc -> t -> t, PrimExpr -> t -> t, RelOp -> t -> t -> t, Assoc -> t -> t, SpecialOp -> t -> t) -> PrimQuery -> t
- foldPrimExpr :: (Attribute -> t, Literal -> t, BinOp -> t -> t -> t, UnOp -> t -> t, AggrOp -> t -> t, [(t, t)] -> t -> t, [t] -> t, Maybe Name -> t -> t, Name -> [t] -> t, Name -> t -> t) -> PrimExpr -> t
Type Declarations
Types
type TableName = String
type Attribute = String
type Name = String
Data types
data PrimQuery
Constructors
| BaseTable TableName Scheme | |
| Project Assoc PrimQuery | |
| Restrict PrimExpr PrimQuery | |
| Group Assoc PrimQuery | |
| Binary RelOp PrimQuery PrimQuery | |
| Special SpecialOp PrimQuery | |
| Empty |
Instances
| Show PrimQuery |
data PrimExpr
Constructors
| AttrExpr Attribute | |
| BinExpr BinOp PrimExpr PrimExpr | |
| UnExpr UnOp PrimExpr | |
| AggrExpr AggrOp PrimExpr | |
| ConstExpr Literal | |
| CaseExpr [(PrimExpr, PrimExpr)] PrimExpr | |
| ListExpr [PrimExpr] | |
| ParamExpr (Maybe Name) PrimExpr | |
| FunExpr Name [PrimExpr] | |
| CastExpr Name PrimExpr | Cast an expression to a given type. |
data BinOp
data AggrOp
Constructors
| AggrCount | |
| AggrSum | |
| AggrAvg | |
| AggrMin | |
| AggrMax | |
| AggrStdDev | |
| AggrStdDevP | |
| AggrVar | |
| AggrVarP | |
| AggrOther String |
data Literal
Constructors
| NullLit | |
| DefaultLit | represents a default value |
| BoolLit Bool | |
| StringLit String | |
| IntegerLit Integer | |
| DoubleLit Double | |
| DateLit CalendarTime | |
| OtherLit String | used for hacking in custom SQL |
Function declarations
extend :: Assoc -> PrimQuery -> PrimQuery
Creates a projection of some attributes while keeping all other attributes in the relation visible too.
attributes :: PrimQuery -> Scheme
Returns the schema (the attributes) of a query
attrInExpr :: PrimExpr -> Scheme
Returns all attributes in an expression.
attrInOrder :: [OrderExpr] -> Scheme
Returns all attributes in a list of ordering expressions.
isAggregate :: PrimExpr -> Bool
isConstant :: PrimExpr -> Bool
Determines if a primitive expression represents a constant or is an expression only involving constants.