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refactor: simplify join conditions logic

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steve-chavez
2022-10-19 19:49:43 -05:00
committed by Steve Chavez
parent 922da4520f
commit 5f5a0c7764
5 changed files with 52 additions and 58 deletions
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src/PostgREST/Plan.hs
+21 -26
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@@ -95,7 +95,7 @@ readPlan :: QualifiedIdentifier -> AppConfig -> SchemaCache -> ApiRequest -> Eit
readPlan qi@QualifiedIdentifier{..} AppConfig{configDbMaxRows} SchemaCache{dbRelationships} apiRequest =
mapLeft ApiRequestError $
treeRestrictRange configDbMaxRows (iAction apiRequest) =<<
augmentRequestWithJoin qiSchema dbRelationships =<<
addRels qiSchema dbRelationships Nothing =<<
addLogicTrees apiRequest =<<
addRanges apiRequest =<<
addOrders apiRequest =<<
@@ -118,7 +118,7 @@ initReadRequest rootQi rootAlias =
rootDepth = 0
rootSchema = qiSchema rootQi
rootName = qiName rootQi
initial = Node (ReadPlan [] rootQi rootAlias [] [] [] allRange rootName Nothing Nothing Nothing Nothing rootDepth) []
initial = Node (ReadPlan [] rootQi rootAlias [] [] allRange rootName Nothing [] Nothing Nothing Nothing rootDepth) []
treeEntry :: Depth -> Tree SelectItem -> ReadPlanTree -> ReadPlanTree
treeEntry depth (Node fld@((fn, _),_,alias, hint, joinType) fldForest) (Node q rForest) =
let nxtDepth = succ depth in
@@ -126,7 +126,7 @@ initReadRequest rootQi rootAlias =
[] -> Node q{select=fld:select q} rForest
_ -> Node q $
foldr (treeEntry nxtDepth)
(Node (ReadPlan [] (QualifiedIdentifier rootSchema fn) Nothing [] [] [] allRange fn Nothing alias hint joinType nxtDepth) [])
(Node (ReadPlan [] (QualifiedIdentifier rootSchema fn) Nothing [] [] allRange fn Nothing [] alias hint joinType nxtDepth) [])
fldForest:rForest
-- | Enforces the `max-rows` config on the result
@@ -137,19 +137,18 @@ treeRestrictRange maxRows _ request = pure $ nodeRestrictRange maxRows <$> reque
nodeRestrictRange :: Maybe Integer -> ReadPlan -> ReadPlan
nodeRestrictRange m q@ReadPlan{range_=r} = q{range_=restrictRange m r }
augmentRequestWithJoin :: Schema -> RelationshipsMap -> ReadPlanTree -> Either ApiRequestError ReadPlanTree
augmentRequestWithJoin schema allRels request =
addJoinConditions Nothing <$> addRels schema allRels Nothing request
-- add relationships to the nodes of the tree by traversing the forest while keeping track of the parentNode
addRels :: Schema -> RelationshipsMap -> Maybe ReadPlanTree -> ReadPlanTree -> Either ApiRequestError ReadPlanTree
addRels schema allRels parentNode (Node query@ReadPlan{from=tbl,relName,relHint,depth} forest) =
case parentNode of
Just (Node ReadPlan{from=parentNodeQi, fromAlias=aliasQi} _) ->
let newFrom r = if qiName tbl == relName then relForeignTable r else tbl
newReadPlan = (\r ->
if not $ relIsSelf r -- add alias if self rel TODO consolidate aliasing in another function
then query{from=newFrom r, relToParent=Just r}
else query{from=newFrom r, relToParent=Just r, fromAlias=Just (qiName (newFrom r) <> "_" <> show depth)}
if not $ relIsSelf r -- add alias if self rel
then query{from=newFrom r, relToParent=Just r, relJoinConds=getJoinConditions Nothing aliasQi r}
else
let selfAlias = Just (qiName (newFrom r) <> "_" <> show depth) in
query{from=newFrom r, relToParent=Just r, fromAlias=selfAlias, relJoinConds=getJoinConditions selfAlias aliasQi r}
) <$> rel
origin = if depth == 1 -- Only on depth 1 we check if the root(depth 0) has an alias so the sourceCTEName alias can be found as a relationship
then fromMaybe (qiName parentNodeQi) aliasQi
@@ -163,25 +162,21 @@ addRels schema allRels parentNode (Node query@ReadPlan{from=tbl,relName,relHint,
updateForest :: Maybe ReadPlanTree -> Either ApiRequestError [ReadPlanTree]
updateForest rq = addRels schema allRels rq `traverse` forest
-- applies aliasing to join conditions TODO refactor, this should go into the querybuilder module
addJoinConditions :: Maybe Alias -> ReadPlanTree -> ReadPlanTree
addJoinConditions _ (Node node@ReadPlan{fromAlias=tblAlias, relToParent=Nothing} forest) = Node node (addJoinConditions tblAlias <$> forest)
addJoinConditions _ (Node node@ReadPlan{fromAlias=tblAlias, relToParent=Just ComputedRelationship{}} forest) = Node node (addJoinConditions tblAlias <$> forest)
addJoinConditions previousAlias (Node query@ReadPlan{fromAlias=tblAlias, relToParent=Just Relationship{relTable=qi,relForeignTable=fQi,relCardinality=card}} forest) =
Node query{joinConditions=joinConds} (addJoinConditions tblAlias <$> forest)
getJoinConditions :: Maybe Alias -> Maybe Alias -> Relationship -> [JoinCondition]
getJoinConditions _ _ ComputedRelationship{} = []
getJoinConditions tblAlias parentAlias Relationship{relTable=qi,relForeignTable=fQi,relCardinality=card} =
case card of
M2M (Junction QualifiedIdentifier{qiName=jtn} _ _ jcols1 jcols2) ->
(toJoinCondition Nothing Nothing ftN jtn <$> jcols2) ++ (toJoinCondition parentAlias tblAlias tN jtn <$> jcols1)
O2M _ cols ->
toJoinCondition parentAlias tblAlias tN ftN <$> cols
M2O _ cols ->
toJoinCondition parentAlias tblAlias tN ftN <$> cols
O2O _ cols ->
toJoinCondition parentAlias tblAlias tN ftN <$> cols
where
QualifiedIdentifier{qiSchema=tSchema, qiName=tN} = qi
QualifiedIdentifier{qiName=ftN} = fQi
joinConds =
case card of
M2M (Junction QualifiedIdentifier{qiName=jtn} _ _ jcols1 jcols2) ->
(toJoinCondition Nothing Nothing ftN jtn <$> jcols2) ++ (toJoinCondition previousAlias tblAlias tN jtn <$> jcols1)
O2M _ cols ->
toJoinCondition previousAlias tblAlias tN ftN <$> cols
M2O _ cols ->
toJoinCondition previousAlias tblAlias tN ftN <$> cols
O2O _ cols ->
toJoinCondition previousAlias tblAlias tN ftN <$> cols
toJoinCondition :: Maybe Alias -> Maybe Alias -> Text -> Text -> (FieldName, FieldName) -> JoinCondition
toJoinCondition prAl newAl tb ftb (c, fc) =
let qi1 = QualifiedIdentifier tSchema ftb