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
committed by
Steve Chavez
Steve Chavez
parent
b2b92e75cc
commit
06c9e246f4
@@ -24,6 +24,7 @@ import Data.Tree (Tree (..))
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import PostgREST.DbStructure.Identifiers (QualifiedIdentifier (..))
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import PostgREST.DbStructure.Proc (ProcParam (..))
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import PostgREST.DbStructure.Relationship (Cardinality (..),
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Junction (..),
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Relationship (..))
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import PostgREST.Request.Preferences (PreferResolution (..))
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@@ -36,10 +37,10 @@ import PostgREST.Request.Types
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import Protolude
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readRequestToQuery :: ReadRequest -> SQL.Snippet
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readRequestToQuery (Node (Select colSelects mainQi tblAlias implJoins logicForest joinConditions_ ordts range, _) forest) =
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readRequestToQuery (Node (Select colSelects mainQi tblAlias logicForest joinConditions_ ordts range, (_, rel, _, _, _, _)) forest) =
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"SELECT " <>
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intercalateSnippet ", " ((pgFmtSelectItem qi <$> colSelects) ++ selects) <> " " <>
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"FROM " <> SQL.sql (BS.intercalate ", " (tabl : implJs)) <> " " <>
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"FROM " <> SQL.sql tabl <> implicitJoinF rel <> " " <>
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intercalateSnippet " " joins <> " " <>
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(if null logicForest && null joinConditions_
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then mempty
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@@ -47,12 +48,12 @@ readRequestToQuery (Node (Select colSelects mainQi tblAlias implJoins logicFores
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orderF qi ordts <> " " <>
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limitOffsetF range
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where
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implJs = fromQi <$> implJoins
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tabl = fromQi mainQi <> maybe mempty (\a -> " AS " <> pgFmtIdent a) tblAlias
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qi = maybe mainQi (QualifiedIdentifier mempty) tblAlias
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(selects, joins) = foldr getSelectsJoins ([],[]) forest
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getSelectsJoins :: ReadRequest -> ([SQL.Snippet], [SQL.Snippet]) -> ([SQL.Snippet], [SQL.Snippet])
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getSelectsJoins (Node (_, (_, Nothing, _, _, _, _)) _) _ = ([], [])
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getSelectsJoins rr@(Node (_, (name, Just Relationship{relCardinality=card,relTable=QualifiedIdentifier{qiName=table}}, alias, _, joinType, _)) _) (selects,joins) =
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let
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subquery = readRequestToQuery rr
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@@ -74,7 +75,6 @@ getSelectsJoins rr@(Node (_, (name, Just Relationship{relCardinality=card,relTab
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) localTableName $ if joinType == Just JTInner then SQL.sql localTableName <> " IS NOT NULL" else "TRUE")
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in
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(sel:selects, joi:joins)
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getSelectsJoins (Node (_, (_, Nothing, _, _, _, _)) _) _ = ([], [])
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mutateRequestToQuery :: MutateRequest -> SQL.Snippet
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mutateRequestToQuery (Insert mainQi iCols body onConflct putConditions returnings) =
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@@ -218,20 +218,19 @@ requestToCallProcQuery (FunctionCall qi params args returnsScalar multipleCall r
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-- See https://github.com/PostgREST/postgrest/issues/2009#issuecomment-977473031
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-- Only for the nodes that have an INNER JOIN linked to the root level.
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readRequestToCountQuery :: ReadRequest -> SQL.Snippet
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readRequestToCountQuery (Node (Select{from=mainQi, fromAlias=tblAlias, implicitJoins=implJoins, where_=logicForest, joinConditions=joinConditions_}, _) forest) =
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"SELECT 1 FROM " <> SQL.sql (BS.intercalate ", " (tabl : implJs)) <>
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readRequestToCountQuery (Node (Select{from=mainQi, fromAlias=tblAlias, where_=logicForest, joinConditions=joinConditions_}, (_, rel, _, _, _, _)) forest) =
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"SELECT 1 FROM " <> SQL.sql tabl <> implicitJoinF rel <>
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(if null logicForest && null joinConditions_ && null subQueries
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then mempty
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else " WHERE " ) <>
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intercalateSnippet " AND " (
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map (pgFmtLogicTree treeQi) logicForest ++
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map (pgFmtLogicTree qi) logicForest ++
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map pgFmtJoinCondition joinConditions_ ++
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subQueries
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)
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where
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treeQi = maybe mainQi (QualifiedIdentifier (qiSchema mainQi)) tblAlias
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qi = maybe mainQi (QualifiedIdentifier mempty) tblAlias
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tabl = fromQi mainQi <> maybe mempty (\a -> " AS " <> pgFmtIdent a) tblAlias
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implJs = fromQi <$> implJoins
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subQueries = foldr existsSubquery [] forest
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existsSubquery :: ReadRequest -> [SQL.Snippet] -> [SQL.Snippet]
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existsSubquery readReq@(Node (_, (_, _, _, _, joinType, _)) _) rest =
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@@ -241,3 +240,8 @@ readRequestToCountQuery (Node (Select{from=mainQi, fromAlias=tblAlias, implicitJ
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limitedQuery :: SQL.Snippet -> Maybe Integer -> SQL.Snippet
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limitedQuery query maxRows = query <> SQL.sql (maybe mempty (\x -> " LIMIT " <> BS.pack (show x)) maxRows)
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implicitJoinF :: Maybe Relationship -> SQL.Snippet
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implicitJoinF rel = case relCardinality <$> rel of
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Just (M2M Junction{junTable=jt}) -> ", " <> SQL.sql (fromQi jt)
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_ -> mempty
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@@ -87,7 +87,7 @@ initReadRequest rootQi rootAlias =
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rootDepth = 0
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rootSchema = qiSchema rootQi
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rootName = qiName rootQi
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initial = Node (Select [] rootQi rootAlias [] [] [] [] allRange, (rootName, Nothing, Nothing, Nothing, Nothing, rootDepth)) []
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initial = Node (Select [] rootQi rootAlias [] [] [] allRange, (rootName, Nothing, Nothing, Nothing, Nothing, rootDepth)) []
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treeEntry :: Depth -> Tree SelectItem -> ReadRequest -> ReadRequest
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treeEntry depth (Node fld@((fn, _),_,alias, hint, joinType) fldForest) (Node (q, i) rForest) =
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let nxtDepth = succ depth in
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@@ -95,7 +95,7 @@ initReadRequest rootQi rootAlias =
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[] -> Node (q {select=fld:select q}, i) rForest
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_ -> Node (q, i) $
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foldr (treeEntry nxtDepth)
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(Node (Select [] (QualifiedIdentifier rootSchema fn) Nothing [] [] [] [] allRange,
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(Node (Select [] (QualifiedIdentifier rootSchema fn) Nothing [] [] [] allRange,
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(fn, Nothing, alias, hint, joinType, nxtDepth)) [])
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fldForest:rForest
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@@ -109,16 +109,19 @@ treeRestrictRange maxRows _ request = pure $ nodeRestrictRange maxRows <$> reque
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augmentRequestWithJoin :: Schema -> RelationshipsMap -> ReadRequest -> Either ApiRequestError ReadRequest
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augmentRequestWithJoin schema allRels request =
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addRels schema allRels Nothing request
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>>= addJoinConditions Nothing
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addJoinConditions Nothing <$> addRels schema allRels Nothing request
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addRels :: Schema -> RelationshipsMap -> Maybe ReadRequest -> ReadRequest -> Either ApiRequestError ReadRequest
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addRels schema allRels parentNode (Node (query@Select{from=tbl}, (nodeName, _, alias, hint, joinType, depth)) forest) =
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case parentNode of
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Just (Node (Select{from=parentNodeQi, fromAlias=aliasQi}, _) _) ->
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let newFrom r = if qiName tbl == nodeName then relForeignTable r else tbl
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newReadNode = (\r -> (query{from=newFrom r}, (nodeName, Just r, alias, hint, joinType, depth))) <$> rel
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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
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newReadNode = (\r ->
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if not $ relIsSelf r -- add alias if self rel TODO consolidate aliasing in another function
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then (query{from=newFrom r}, (nodeName, Just r, alias, hint, joinType, depth))
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else (query{from=newFrom r, fromAlias=Just (qiName (newFrom r) <> "_" <> show depth)}, (nodeName, Just r, alias, hint, joinType, depth))
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) <$> rel
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origin = if depth == 1 -- Only on depth 1 we check if the root(depth 0) has an alias so the sourceCTEName alias can be found as a relationship
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then fromMaybe (qiName parentNodeQi) aliasQi
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else qiName parentNodeQi
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rel = findRel schema allRels origin nodeName hint
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@@ -131,6 +134,27 @@ addRels schema allRels parentNode (Node (query@Select{from=tbl}, (nodeName, _, a
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updateForest :: Maybe ReadRequest -> Either ApiRequestError [ReadRequest]
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updateForest rq = addRels schema allRels rq `traverse` forest
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-- applies aliasing to join conditions TODO refactor, this should go into the querybuilder module
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addJoinConditions :: Maybe Alias -> ReadRequest -> ReadRequest
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addJoinConditions _ (Node node@(Select{fromAlias=tblAlias}, (_, Nothing, _, _, _, _)) forest) = Node node (addJoinConditions tblAlias <$> forest)
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addJoinConditions previousAlias (Node (query@Select{fromAlias=tblAlias}, nodeProps@(_, Just (Relationship QualifiedIdentifier{qiSchema=tSchema, qiName=tN} QualifiedIdentifier{qiName=ftN} _ card _ _), _, _, _, _)) forest) =
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Node (query{joinConditions=joinConds}, nodeProps) (addJoinConditions tblAlias <$> forest)
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where
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joinConds =
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case card of
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M2M (Junction QualifiedIdentifier{qiName=jtn} _ _ jcols1 jcols2) ->
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(toJoinCondition Nothing Nothing ftN jtn <$> jcols2) ++ (toJoinCondition previousAlias tblAlias tN jtn <$> jcols1)
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O2M _ cols ->
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toJoinCondition previousAlias tblAlias tN ftN <$> cols
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M2O _ cols ->
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toJoinCondition previousAlias tblAlias tN ftN <$> cols
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toJoinCondition :: Maybe Alias -> Maybe Alias -> Text -> Text -> (FieldName, FieldName) -> JoinCondition
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toJoinCondition prAl newAl tb ftb (c, fc) =
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let qi1 = QualifiedIdentifier tSchema ftb
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qi2 = QualifiedIdentifier tSchema tb in
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JoinCondition (maybe qi1 (QualifiedIdentifier mempty) newAl, fc)
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(maybe qi2 (QualifiedIdentifier mempty) prAl, c)
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-- Finds a relationship between an origin and a target in the request:
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-- /origin?select=target(*) If more than one relationship is found then the
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-- request is ambiguous and we return an error. In that case the request can
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@@ -210,46 +234,6 @@ findRel schema allRels origin target hint =
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)
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) $ fromMaybe mempty $ HM.lookup (QualifiedIdentifier schema origin, schema) allRels
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-- previousAlias is only used for the case of self joins
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addJoinConditions :: Maybe Alias -> ReadRequest -> Either ApiRequestError ReadRequest
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addJoinConditions previousAlias (Node node@(query@Select{from=tbl,fromAlias=tblAlias}, nodeProps@(_, rel, _, _, _, depth)) forest) =
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case rel of
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Just r@Relationship{relCardinality=M2M Junction{junTable}} ->
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let rq = augmentQuery r in
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Node (rq{implicitJoins=junTable:implicitJoins rq}, nodeProps) <$> updatedForest
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Just r -> Node (augmentQuery r, nodeProps) <$> updatedForest
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Nothing -> Node node <$> updatedForest
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where
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newAlias = if depth == 0
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then tblAlias -- only use the alias on the root node(depth 0) for when the sourceCTEName alias is used for joining
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else case relIsSelf <$> rel of -- no need to apply the self reference alias on depth 0 only on the next depths
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Just True -> Just (qiName tbl <> "_" <> show depth)
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_ -> Nothing
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augmentQuery r =
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foldr
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(\jc rq@Select{joinConditions=jcs} -> rq{joinConditions=jc:jcs})
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query{fromAlias=newAlias}
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(getJoinConditions previousAlias newAlias r)
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updatedForest = addJoinConditions newAlias `traverse` forest
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-- previousAlias and newAlias are used in the case of self joins
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getJoinConditions :: Maybe Alias -> Maybe Alias -> Relationship -> [JoinCondition]
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getJoinConditions previousAlias newAlias (Relationship QualifiedIdentifier{qiSchema=tSchema, qiName=tN} QualifiedIdentifier{qiName=ftN} _ card _ _) =
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case card of
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M2M (Junction QualifiedIdentifier{qiName=jtn} _ _ jcols1 jcols2) ->
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(toJoinCondition previousAlias newAlias tN jtn <$> jcols1) ++ (toJoinCondition Nothing Nothing ftN jtn <$> jcols2)
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O2M _ cols ->
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toJoinCondition previousAlias newAlias tN ftN <$> cols
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M2O _ cols ->
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toJoinCondition previousAlias newAlias tN ftN <$> cols
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where
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toJoinCondition :: Maybe Alias -> Maybe Alias -> Text -> Text -> (FieldName, FieldName) -> JoinCondition
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toJoinCondition prAl newAl tb ftb (c, fc) =
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let qi1 = QualifiedIdentifier tSchema tb
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qi2 = QualifiedIdentifier tSchema ftb in
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JoinCondition (maybe qi1 (QualifiedIdentifier mempty) prAl, c)
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(maybe qi2 (QualifiedIdentifier mempty) newAl, fc)
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addFilters :: ApiRequest -> ReadRequest -> Either ApiRequestError ReadRequest
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addFilters ApiRequest{..} rReq =
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foldr addFilterToNode (Right rReq) flts
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@@ -31,10 +31,8 @@ type SelectItem = (Field, Maybe Cast, Maybe Alias, Maybe Hint, Maybe JoinType)
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data ReadQuery = Select
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{ select :: [SelectItem]
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, from :: QualifiedIdentifier
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-- ^ A table alias is used in case of self joins
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, fromAlias :: Maybe Alias
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-- ^ Only used for Many to Many joins. Parent and Child joins use explicit joins.
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, implicitJoins :: [QualifiedIdentifier]
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-- ^ A table alias is used in case of self joins
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, where_ :: [LogicTree]
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, joinConditions :: [JoinCondition]
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, order :: [OrderTerm]
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