5f5dd31 · project-m36 · git.iko.soy

RelationExpr.hs+5−6

@@ -198,12 +198,11 @@ evalContextExpr (Assign relVarName expr) = do

198evalContextExpr (Insert relVarName relExpr) = evalContextExpr $ Assign relVarName (Union relExpr (RelationVariable relVarName))

199

200--assign empty rel until restriction is implemented

201−evalContextExpr (Delete relVarName) = do

201+evalContextExpr (Delete relVarName predicate) = do

202− relVarTable <- liftM relationVariables get

202+ updatedRel <- evalRelationalExpr (Restrict (NotPredicate predicate) (RelationVariable relVarName))

203− case M.lookup relVarName relVarTable of

203+ case updatedRel of

204− Nothing -> return $ Just (RelVarNotDefinedError relVarName)

204+ Left err -> return $ Just err

205− Just rel -> setRelVar relVarName (Relation (attributes rel) emptyTupleSet)

205+ Right rel -> setRelVar relVarName rel

206−

207

206

208--union of restricted+updated portion and the unrestricted+unupdated portion

207--union of restricted+updated portion and the unrestricted+unupdated portion

209evalContextExpr (Update relVarName attrAssignments restrictionPredicateExpr) = do

208evalContextExpr (Update relVarName attrAssignments restrictionPredicateExpr) = do

RelationTupleSet.hs−1

@@ -3,7 +3,6 @@ import RelationType

3import RelationTuple

4import RelationalError

5import qualified Data.Map as M

6−import qualified Data.Set as S

7import qualified Data.HashSet as HS

6import qualified Data.HashSet as HS

8import Control.Monad

7import Control.Monad

9

8

RelationType.hs+2−1

@@ -76,9 +76,10 @@ instance Eq InclusionDependency where

76--Database context expressions modify the database context while relational expressions do not

77data DatabaseExpr where

78 Define :: String -> Attributes -> DatabaseExpr

79+ Undefine :: String -> DatabaseExpr --forget existence of relvar X

79 Assign :: String -> RelationalExpr -> DatabaseExpr

80 Assign :: String -> RelationalExpr -> DatabaseExpr

80 Insert :: String -> RelationalExpr -> DatabaseExpr

81 Insert :: String -> RelationalExpr -> DatabaseExpr

81− Delete :: String -> DatabaseExpr -- needs restriction support

82+ Delete :: String -> RestrictionPredicateExpr -> DatabaseExpr

82 Update :: String -> M.Map String Atom -> RestrictionPredicateExpr -> DatabaseExpr -- needs restriction support

83 Update :: String -> M.Map String Atom -> RestrictionPredicateExpr -> DatabaseExpr -- needs restriction support

83 AddInclusionDependency :: InclusionDependency -> DatabaseExpr

84 AddInclusionDependency :: InclusionDependency -> DatabaseExpr

84 MultipleExpr :: [DatabaseExpr] -> DatabaseExpr

85 MultipleExpr :: [DatabaseExpr] -> DatabaseExpr

TutorialDInterpreter.hs+2−1

@@ -204,7 +204,8 @@ deleteP :: Parser DatabaseExpr

204deleteP = do

205 reservedOp "delete"

206 relVarName <- identifier

207+ predicate <- option TruePredicate (reservedOp "where" *> restrictionPredicateP)

207− return $ Delete relVarName

208+ return $ Delete relVarName predicate

208

209

209updateP :: Parser DatabaseExpr

210updateP :: Parser DatabaseExpr

210updateP = do

211updateP = do

TutorialDInterpreterTest.hs+2−1

@@ -30,7 +30,8 @@ main = do

30 ("x:=true where true and true", Right relationTrue),

31 ("x:=true=true", Right relationTrue),

32 ("x:=true=false", Right relationFalse),

33− ("x:=relation {b int, a char}; insert x relation{tuple{b int(5), a char(\"spam\")}}", mkRelation simpleCAttributes (HS.fromList [RelationTuple $ M.fromList [("a", StringAtom "spam"), ("b", IntAtom 5)]]))

33+ ("x:=relation {b int, a char}; insert x relation{tuple{b int(5), a char(\"spam\")}}", mkRelation simpleCAttributes (HS.fromList [RelationTuple $ M.fromList [("a", StringAtom "spam"), ("b", IntAtom 5)]])),

34+ ("x:=relation{tuple{b int(5),a char(\"spam\")},tuple{b int(6),a char(\"sam\")}}; delete x where b=6", mkRelation simpleCAttributes $ HS.fromList [RelationTuple $ M.fromList [("a", StringAtom "spam"), ("b", IntAtom 5)]])

34 ]

35 ]

35 simpleAAttributes = M.fromList [("a", Attribute "a" IntAtomType)]

36 simpleAAttributes = M.fromList [("a", Attribute "a" IntAtomType)]

36 simpleBAttributes = M.fromList [("d", Attribute "d" IntAtomType)]

37 simpleBAttributes = M.fromList [("d", Attribute "d" IntAtomType)]