refactor: simplify addJoinConditions

* remove unnecessary Either
* remove implicitJoins from ReadQuery
* remove unnecessary foldr in addJoinConditions
* move aliasing to addRels
This commit is contained in:
steve-chavez
2022-08-17 22:50:06 -05:00
committed by Steve Chavez
parent b2b92e75cc
commit 06c9e246f4
3 changed files with 44 additions and 58 deletions
+30 -46
View File
@@ -87,7 +87,7 @@ initReadRequest rootQi rootAlias =
rootDepth = 0
rootSchema = qiSchema rootQi
rootName = qiName rootQi
initial = Node (Select [] rootQi rootAlias [] [] [] [] allRange, (rootName, Nothing, Nothing, Nothing, Nothing, rootDepth)) []
initial = Node (Select [] rootQi rootAlias [] [] [] allRange, (rootName, Nothing, Nothing, Nothing, Nothing, rootDepth)) []
treeEntry :: Depth -> Tree SelectItem -> ReadRequest -> ReadRequest
treeEntry depth (Node fld@((fn, _),_,alias, hint, joinType) fldForest) (Node (q, i) rForest) =
let nxtDepth = succ depth in
@@ -95,7 +95,7 @@ initReadRequest rootQi rootAlias =
[] -> Node (q {select=fld:select q}, i) rForest
_ -> Node (q, i) $
foldr (treeEntry nxtDepth)
(Node (Select [] (QualifiedIdentifier rootSchema fn) Nothing [] [] [] [] allRange,
(Node (Select [] (QualifiedIdentifier rootSchema fn) Nothing [] [] [] allRange,
(fn, Nothing, alias, hint, joinType, nxtDepth)) [])
fldForest:rForest
@@ -109,16 +109,19 @@ treeRestrictRange maxRows _ request = pure $ nodeRestrictRange maxRows <$> reque
augmentRequestWithJoin :: Schema -> RelationshipsMap -> ReadRequest -> Either ApiRequestError ReadRequest
augmentRequestWithJoin schema allRels request =
addRels schema allRels Nothing request
>>= addJoinConditions Nothing
addJoinConditions Nothing <$> addRels schema allRels Nothing request
addRels :: Schema -> RelationshipsMap -> Maybe ReadRequest -> ReadRequest -> Either ApiRequestError ReadRequest
addRels schema allRels parentNode (Node (query@Select{from=tbl}, (nodeName, _, alias, hint, joinType, depth)) forest) =
case parentNode of
Just (Node (Select{from=parentNodeQi, fromAlias=aliasQi}, _) _) ->
let newFrom r = if qiName tbl == nodeName then relForeignTable r else tbl
newReadNode = (\r -> (query{from=newFrom r}, (nodeName, Just r, alias, hint, joinType, depth))) <$> rel
origin = if depth == 1 -- Only on depth 1 we check if the parent(depth 0) has an alias so the sourceCTEName alias can be found as a relationship
newReadNode = (\r ->
if not $ relIsSelf r -- add alias if self rel TODO consolidate aliasing in another function
then (query{from=newFrom r}, (nodeName, Just r, alias, hint, joinType, depth))
else (query{from=newFrom r, fromAlias=Just (qiName (newFrom r) <> "_" <> show depth)}, (nodeName, Just r, alias, hint, joinType, depth))
) <$> rel
origin = if depth == 1 -- Only on depth 1 we check if the root(depth 0) has an alias so the sourceCTEName alias can be found as a relationship
then fromMaybe (qiName parentNodeQi) aliasQi
else qiName parentNodeQi
rel = findRel schema allRels origin nodeName hint
@@ -131,6 +134,27 @@ addRels schema allRels parentNode (Node (query@Select{from=tbl}, (nodeName, _, a
updateForest :: Maybe ReadRequest -> Either ApiRequestError [ReadRequest]
updateForest rq = addRels schema allRels rq `traverse` forest
-- applies aliasing to join conditions TODO refactor, this should go into the querybuilder module
addJoinConditions :: Maybe Alias -> ReadRequest -> ReadRequest
addJoinConditions _ (Node node@(Select{fromAlias=tblAlias}, (_, Nothing, _, _, _, _)) forest) = Node node (addJoinConditions tblAlias <$> forest)
addJoinConditions previousAlias (Node (query@Select{fromAlias=tblAlias}, nodeProps@(_, Just (Relationship QualifiedIdentifier{qiSchema=tSchema, qiName=tN} QualifiedIdentifier{qiName=ftN} _ card _ _), _, _, _, _)) forest) =
Node (query{joinConditions=joinConds}, nodeProps) (addJoinConditions tblAlias <$> forest)
where
joinConds =
case card of
M2M (Junction QualifiedIdentifier{qiName=jtn} _ _ jcols1 jcols2) ->
(toJoinCondition Nothing Nothing ftN jtn <$> jcols2) ++ (toJoinCondition previousAlias tblAlias tN jtn <$> jcols1)
O2M _ cols ->
toJoinCondition previousAlias tblAlias tN ftN <$> cols
M2O _ cols ->
toJoinCondition previousAlias tblAlias tN ftN <$> cols
toJoinCondition :: Maybe Alias -> Maybe Alias -> Text -> Text -> (FieldName, FieldName) -> JoinCondition
toJoinCondition prAl newAl tb ftb (c, fc) =
let qi1 = QualifiedIdentifier tSchema ftb
qi2 = QualifiedIdentifier tSchema tb in
JoinCondition (maybe qi1 (QualifiedIdentifier mempty) newAl, fc)
(maybe qi2 (QualifiedIdentifier mempty) prAl, c)
-- Finds a relationship between an origin and a target in the request:
-- /origin?select=target(*) If more than one relationship is found then the
-- request is ambiguous and we return an error. In that case the request can
@@ -210,46 +234,6 @@ findRel schema allRels origin target hint =
)
) $ fromMaybe mempty $ HM.lookup (QualifiedIdentifier schema origin, schema) allRels
-- previousAlias is only used for the case of self joins
addJoinConditions :: Maybe Alias -> ReadRequest -> Either ApiRequestError ReadRequest
addJoinConditions previousAlias (Node node@(query@Select{from=tbl,fromAlias=tblAlias}, nodeProps@(_, rel, _, _, _, depth)) forest) =
case rel of
Just r@Relationship{relCardinality=M2M Junction{junTable}} ->
let rq = augmentQuery r in
Node (rq{implicitJoins=junTable:implicitJoins rq}, nodeProps) <$> updatedForest
Just r -> Node (augmentQuery r, nodeProps) <$> updatedForest
Nothing -> Node node <$> updatedForest
where
newAlias = if depth == 0
then tblAlias -- only use the alias on the root node(depth 0) for when the sourceCTEName alias is used for joining
else case relIsSelf <$> rel of -- no need to apply the self reference alias on depth 0 only on the next depths
Just True -> Just (qiName tbl <> "_" <> show depth)
_ -> Nothing
augmentQuery r =
foldr
(\jc rq@Select{joinConditions=jcs} -> rq{joinConditions=jc:jcs})
query{fromAlias=newAlias}
(getJoinConditions previousAlias newAlias r)
updatedForest = addJoinConditions newAlias `traverse` forest
-- previousAlias and newAlias are used in the case of self joins
getJoinConditions :: Maybe Alias -> Maybe Alias -> Relationship -> [JoinCondition]
getJoinConditions previousAlias newAlias (Relationship QualifiedIdentifier{qiSchema=tSchema, qiName=tN} QualifiedIdentifier{qiName=ftN} _ card _ _) =
case card of
M2M (Junction QualifiedIdentifier{qiName=jtn} _ _ jcols1 jcols2) ->
(toJoinCondition previousAlias newAlias tN jtn <$> jcols1) ++ (toJoinCondition Nothing Nothing ftN jtn <$> jcols2)
O2M _ cols ->
toJoinCondition previousAlias newAlias tN ftN <$> cols
M2O _ cols ->
toJoinCondition previousAlias newAlias tN ftN <$> cols
where
toJoinCondition :: Maybe Alias -> Maybe Alias -> Text -> Text -> (FieldName, FieldName) -> JoinCondition
toJoinCondition prAl newAl tb ftb (c, fc) =
let qi1 = QualifiedIdentifier tSchema tb
qi2 = QualifiedIdentifier tSchema ftb in
JoinCondition (maybe qi1 (QualifiedIdentifier mempty) prAl, c)
(maybe qi2 (QualifiedIdentifier mempty) newAl, fc)
addFilters :: ApiRequest -> ReadRequest -> Either ApiRequestError ReadRequest
addFilters ApiRequest{..} rReq =
foldr addFilterToNode (Right rReq) flts