5f5dd31 · project-m36 · git.iko.soy

git.iko.soy/project-m36

implement Tutorial D delete with predicate

commit5f5dd313fd9d56c9c72e4d9b1762521e47b00936 authorAgentM <agentm@themactionfaction.com> dateWed 28 Jan 2015, 22:22 (12 years ago) parent7f32362

5 files changed+11−10

compare with master

unifiedsplit

RelationExpr.hs+5−6 RelationTupleSet.hs−1 RelationType.hs+2−1 TutorialDInterpreter.hs+2−1 TutorialDInterpreterTest.hs+2−1

RelationExpr.hs+5−6

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

198198evalContextExpr (Insert relVarName relExpr) = evalContextExpr $ Assign relVarName (Union relExpr (RelationVariable relVarName))

199199

200200--assign empty rel until restriction is implemented

201−evalContextExpr (Delete relVarName) = do

202− relVarTable <- liftM relationVariables get

203− case M.lookup relVarName relVarTable of

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

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

206−

201+evalContextExpr (Delete relVarName predicate) = do

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

203+ case updatedRel of

204+ Left err -> return $ Just err

205+ Right rel -> setRelVar relVarName rel

207206

208207--union of restricted+updated portion and the unrestricted+unupdated portion

209208evalContextExpr (Update relVarName attrAssignments restrictionPredicateExpr) = do

RelationTupleSet.hs−1

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

33import RelationTuple

44import RelationalError

55import qualified Data.Map as M

6−import qualified Data.Set as S

76import qualified Data.HashSet as HS

87import Control.Monad

RelationType.hs+2−1

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

7676--Database context expressions modify the database context while relational expressions do not

7777data DatabaseExpr where

7878 Define :: String -> Attributes -> DatabaseExpr

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

7980 Assign :: String -> RelationalExpr -> DatabaseExpr

8081 Insert :: String -> RelationalExpr -> DatabaseExpr

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

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

8283 Update :: String -> M.Map String Atom -> RestrictionPredicateExpr -> DatabaseExpr -- needs restriction support

8384 AddInclusionDependency :: InclusionDependency -> DatabaseExpr

8485 MultipleExpr :: [DatabaseExpr] -> DatabaseExpr

TutorialDInterpreter.hs+2−1

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

204204deleteP = do

205205 reservedOp "delete"

206206 relVarName <- identifier

207− return $ Delete relVarName

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

208+ return $ Delete relVarName predicate

208209

209210updateP :: Parser DatabaseExpr

210211updateP = do

TutorialDInterpreterTest.hs+2−1

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

3030 ("x:=true where true and true", Right relationTrue),

3131 ("x:=true=true", Right relationTrue),

3232 ("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)]])

3435 ]

3536 simpleAAttributes = M.fromList [("a", Attribute "a" IntAtomType)]

3637 simpleBAttributes = M.fromList [("d", Attribute "d" IntAtomType)]