Only alias tables on self join cases
This commit is contained in:
steve-chavez
committed by
Steve Chávez
Steve Chávez
parent
243e692192
commit
edae60f8c1
@@ -1,6 +1,7 @@
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{-# LANGUAGE FlexibleContexts #-}
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{-# LANGUAGE DuplicateRecordFields #-}
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{-# LANGUAGE LambdaCase #-}
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{-# LANGUAGE MultiWayIf #-}
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module PostgREST.DbRequestBuilder (
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readRequest
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, mutateRequest
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@@ -60,21 +61,21 @@ readRequest maxRows allRels proc apiRequest =
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_ -> Nothing
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-- Build tree with a Level attribute so when an embed occurs and the parent node has the same name as the child we can differentiate them by having
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-- an alias like "node_lvl", this is related to issue #987.
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-- Build tree with a Depth attribute so when a self join occurs we can differentiate the parent and child tables by having
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-- an alias like "table_depth", this is related to issue #987.
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buildReadRequest :: [Tree SelectItem] -> ReadRequest
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buildReadRequest fieldTree =
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let rootLvl = 1
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let rootDepth = 0
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rootNodeName = if action == ActionRead then rootTableName else sourceCTEName in
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foldr (treeEntry rootLvl) (Node (Select [] [rootNodeName] [] [] [] allRange, (rootNodeName, Nothing, Nothing, Nothing, rootLvl)) []) fieldTree
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foldr (treeEntry rootDepth) (Node (Select [] [rootNodeName] [] [] [] allRange, (rootNodeName, Nothing, Nothing, Nothing, rootDepth)) []) fieldTree
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where
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treeEntry :: Level -> Tree SelectItem -> ReadRequest -> ReadRequest
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treeEntry lvl (Node fld@((fn, _),_,alias,relationDetail) fldForest) (Node (q, i) rForest) =
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let nxtLvl = succ lvl in
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treeEntry :: Depth -> Tree SelectItem -> ReadRequest -> ReadRequest
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treeEntry depth (Node fld@((fn, _),_,alias,relationDetail) fldForest) (Node (q, i) rForest) =
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let nxtDepth = succ depth in
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case fldForest of
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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 nxtLvl) (Node (Select [] [fn] [] [] [] allRange, (fn, Nothing, alias, relationDetail, nxtLvl)) []) fldForest:rForest
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foldr (treeEntry nxtDepth) (Node (Select [] [fn] [] [] [] allRange, (fn, Nothing, alias, relationDetail, nxtDepth)) []) fldForest:rForest
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relations :: [Relation]
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relations = case action of
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@@ -109,7 +110,7 @@ augumentRequestWithJoin schema allRels request =
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>>= addJoinConditions schema
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addRelations :: Schema -> [Relation] -> Maybe ReadRequest -> ReadRequest -> Either ApiRequestError ReadRequest
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addRelations schema allRelations parentNode (Node readNode@(query, (name, _, alias, relationDetail, level)) forest) =
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addRelations schema allRelations parentNode (Node readNode@(query, (name, _, alias, relationDetail, depth)) forest) =
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case parentNode of
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(Just (Node (Select{from=[parentNodeTable]}, _) _)) ->
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Node <$> readNode' <*> forest'
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@@ -121,7 +122,7 @@ addRelations schema allRelations parentNode (Node readNode@(query, (name, _, ali
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rel = note (NoRelationBetween parentNodeTable name)
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$ findRelation schema name parentNodeTable relationDetail
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where
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findRelation s nodeTableName parentNodeTableName Nothing =
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find (\r ->
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s == tableSchema (relTable r) && -- match schema for relation table
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@@ -159,8 +160,8 @@ addRelations schema allRelations parentNode (Node readNode@(query, (name, _, ali
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-- addRelation will turn project_id to project so the above condition will match
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)
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) allRelations
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findRelation s nodeTableName parentNodeTableName (Just rd) =
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findRelation s nodeTableName parentNodeTableName (Just rd) =
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find (\r ->
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s == tableSchema (relTable r) && -- match schema for relation table
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s == tableSchema (relFTable r) && -- match schema for relation foriegn table
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@@ -176,7 +177,7 @@ addRelations schema allRelations parentNode (Node readNode@(query, (name, _, ali
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parentNodeTableName == tableName (relFTable r) && -- && -- match relation foreign table name
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length (relColumns r) == 1 &&
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rd == (colName . unsafeHead . relColumns) r
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)
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)
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@@ -190,17 +191,17 @@ addRelations schema allRelations parentNode (Node readNode@(query, (name, _, ali
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nodeTableName == tableName (relTable r) && -- match relation table name
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parentNodeTableName == tableName (relFTable r) && -- match relation foreign table name
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rd == tableName (fromJust (relLinkTable r))
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)
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)
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)
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) allRelations
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n `colMatches` rc = (toS ("^" <> rc <> "_?(?:|[iI][dD]|[fF][kK])$") :: BS.ByteString) =~ (toS n :: BS.ByteString)
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addRel :: (ReadQuery, (NodeName, Maybe Relation, Maybe Alias, Maybe RelationDetail, Level)) -> Relation -> (ReadQuery, (NodeName, Maybe Relation, Maybe Alias, Maybe RelationDetail, Level))
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addRel (query', (n, _, a, _, lvl)) r = (query' {from=fromRelation}, (n, Just r, a, Nothing, lvl))
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addRel :: (ReadQuery, (NodeName, Maybe Relation, Maybe Alias, Maybe RelationDetail, Depth)) -> Relation -> (ReadQuery, (NodeName, Maybe Relation, Maybe Alias, Maybe RelationDetail, Depth))
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addRel (query', (n, _, a, _, dpth)) r = (query' {from=fromRelation}, (n, Just r, a, Nothing, dpth))
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where fromRelation = map (\t -> if t == n then tableName (relTable r) else t) (from query')
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_ -> n' <$> updateForest (Just (n' forest))
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where
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n' = Node (query, (name, Just r, alias, Nothing, level))
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n' = Node (query, (name, Just r, alias, Nothing, depth))
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t = Table schema name Nothing True -- !!! TODO find another way to get the table from the query
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r = Relation t [] t [] Root Nothing Nothing Nothing
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where
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@@ -208,7 +209,7 @@ addRelations schema allRelations parentNode (Node readNode@(query, (name, _, ali
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updateForest n = mapM (addRelations schema allRelations n) forest
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addJoinConditions :: Schema -> ReadRequest -> Either ApiRequestError ReadRequest
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addJoinConditions schema (Node node@(query, nodeProps@(_, relation, _, _, lvl)) forest) =
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addJoinConditions schema (Node node@(query, nodeProps@(_, relation, _, _, _)) forest) =
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case relation of
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Just Relation{relType=Root} -> Node node <$> updatedForest -- this is the root node
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Just rel@Relation{relType=Parent} -> Node (augmentQuery rel, nodeProps) <$> updatedForest
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@@ -219,31 +220,23 @@ addJoinConditions schema (Node node@(query, nodeProps@(_, relation, _, _, lvl))
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_ -> Left UnknownRelation
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where
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updatedForest = mapM (addJoinConditions schema) forest
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augmentQuery rel = foldr addJoinCondToReadQuery query (getJoinConds lvl rel)
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addJoinCondToReadQuery jc rq@Select{joinConds=jcs} = rq{joinConds=jc:jcs}
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augmentQuery rel = foldr addJoinCond query (getJoinConditions rel)
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addJoinCond :: JoinCondition -> ReadQuery -> ReadQuery
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addJoinCond jc rq@Select{joinConditions=jcs} = rq{joinConditions=jc:jcs}
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getJoinConds :: Integer -> Relation -> [JoinCond]
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getJoinConds level (Relation t cols ft fcs typ lt lc1 lc2) =
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case typ of
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-- JoinCond needs the Level attr to know the tables aliases
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-- The level depends on the sql query structure
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-- Child has the embed as:
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-- SELECT .., COALESCE(SELECT .. FROM ch AS ch_lvl_2 WHERE ch_lvl_2.col = p_lvl_1.col) FROM p AS p_lvl_1
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-- Parent has similar structure regarding the levels
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-- Many has the embed as:
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-- SELECT .., COALESCE(SELECT .. FROM ch AS ch_lvl_2, gch AS gch_lvl_2 WHERE ch_lvl_2.col = gch_lvl_2.col AND p_lvl_1.acol = ch_lvl_2.acol)
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-- FROM p AS p_lvl_1
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Child -> zipWith (toJoinCond (tN, level) (ftN, level - 1)) cols fcs
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Parent -> zipWith (toJoinCond (tN, level) (ftN, level - 1)) cols fcs
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Many -> zipWith (toJoinCond (tN, level) (ltN, level)) cols (fromMaybe [] lc1) ++ zipWith (toJoinCond (ftN, level - 1) (ltN, level)) fcs (fromMaybe [] lc2)
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Root -> undefined
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getJoinConditions :: Relation -> [JoinCondition]
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getJoinConditions (Relation Table{tableSchema=tSchema, tableName=tN} cols Table{tableName=ftN} fcs typ lt lc1 lc2) =
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if | typ == Child || typ == Parent ->
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zipWith (toJoinCondition tN ftN) cols fcs
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| typ == Many ->
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let ltN = fromMaybe "" (tableName <$> lt) in
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zipWith (toJoinCondition tN ltN) cols (fromMaybe [] lc1) ++ zipWith (toJoinCondition ftN ltN) fcs (fromMaybe [] lc2)
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| typ == Root -> undefined
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where
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s = if typ == Parent then "" else tableSchema t
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tN = tableName t
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ftN = tableName ft
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ltN = fromMaybe "" (tableName <$> lt)
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toJoinCond :: (Text, Integer) -> (Text, Integer) -> Column -> Column -> JoinCond
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toJoinCond (tb, tLvl) (ftb, fLvl) c fc = JoinCond (QualifiedIdentifier s tb, colName c, tLvl) (QualifiedIdentifier s ftb, colName fc, fLvl)
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toJoinCondition :: Text -> Text -> Column -> Column -> JoinCondition
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toJoinCondition tb ftb c fc =
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JoinCondition (QualifiedIdentifier tSchema tb, Nothing, colName c)
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(QualifiedIdentifier tSchema ftb, Nothing, colName fc)
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addFiltersOrdersRanges :: ApiRequest -> Either ApiRequestError (ReadRequest -> ReadRequest)
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addFiltersOrdersRanges apiRequest = foldr1 (liftA2 (.)) [
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@@ -218,20 +218,32 @@ requestToCountQuery schema (DbRead (Node (Select{where_=logicForest}, (mainTbl,
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qi = removeSourceCTESchema schema mainTbl
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requestToQuery :: Schema -> Bool -> DbRequest -> SqlQuery
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requestToQuery schema isParent (DbRead (Node (Select colSelects tbls logicForest joinConds_ ordts range, (nodeName, maybeRelation, _, _, level)) forest)) =
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query
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requestToQuery schema isParent (DbRead (Node (Select colSelects tbls logicForest joinConditions_ ordts range, (nodeName, maybeRelation, _, _, depth)) forest)) =
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unwords [
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"SELECT " <> intercalate ", " (map (pgFmtSelectItem qi) colSelects ++ selects),
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"FROM " <> intercalate ", " tables,
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unwords joins,
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("WHERE " <> intercalate " AND " (map (pgFmtLogicTree qi) logicForest ++ map pgFmtJoinCondition joinConds))
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`emptyOnFalse` (null logicForest && null joinConds),
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("ORDER BY " <> intercalate ", " (map (pgFmtOrderTerm qi) ordts)) `emptyOnFalse` null ordts,
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("LIMIT " <> maybe "ALL" show (rangeLimit range) <> " OFFSET " <> show (rangeOffset range)) `emptyOnFalse` (isParent || range == allRange) ]
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where
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mainTbl = fromMaybe nodeName (tableName . relTable <$> maybeRelation)
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tableAlias tbl = tbl <> "_" <> show level
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qi = QualifiedIdentifier "" $ tableAlias mainTbl
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query = unwords [
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"SELECT " <> intercalate ", " (map (pgFmtSelectItem qi) colSelects ++ selects),
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"FROM " <> intercalate ", " (map (\t -> fromQi (removeSourceCTESchema schema t) <> " AS " <> pgFmtIdent (tableAlias t)) tbls),
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unwords joins,
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("WHERE " <> intercalate " AND " (map (pgFmtLogicTree qi) logicForest ++ map pgFmtJoinCond joinConds_))
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`emptyOnFalse` (null logicForest && null joinConds_),
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("ORDER BY " <> intercalate ", " (map (pgFmtOrderTerm qi) ordts)) `emptyOnFalse` null ordts,
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("LIMIT " <> maybe "ALL" show (rangeLimit range) <> " OFFSET " <> show (rangeOffset range)) `emptyOnFalse` (isParent || range == allRange) ]
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isSelfJoin = maybe False (\r -> relType r /= Root && relTable r == relFTable r) maybeRelation
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(qi, tables, joinConds) =
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let depthAlias name dpth = if dpth /= 0 then name <> "_" <> show dpth else name in -- Root node doesn't get aliased
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if isSelfJoin
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then (
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QualifiedIdentifier "" (depthAlias mainTbl depth),
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(\t -> fromQi (removeSourceCTESchema schema t) <> " AS " <> pgFmtIdent (depthAlias t depth)) <$> tbls,
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(\(JoinCondition (qi1, _, c1) (qi2, _, c2)) ->
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JoinCondition (qi1, Just $ depthAlias (qiName qi1) depth, c1)
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(qi2, Just $ depthAlias (qiName qi2) (depth - 1), c2)) <$> joinConditions_)
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else (
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removeSourceCTESchema schema mainTbl,
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fromQi . removeSourceCTESchema schema <$> tbls,
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joinConditions_)
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(joins, selects) = foldr getQueryParts ([],[]) forest
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@@ -423,11 +435,12 @@ pgFmtFilter table (Filter fld (OpExpr hasNot oper)) = notOp <> " " <> case oper
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(toS (pgFmtLit v) <> "::unknown ")
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(find ((==) . toLower $ v) ["null","true","false"])
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pgFmtJoinCond :: JoinCond -> SqlFragment
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pgFmtJoinCond (JoinCond (qi, cName, lvl) (fQi, fcName, fLvl)) =
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let qiAlias = QualifiedIdentifier "" (qiName qi <> "_" <> show lvl)
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fQiAlias = QualifiedIdentifier "" (qiName fQi <> "_" <> show fLvl) in
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pgFmtColumn qiAlias cName <> " = " <> pgFmtColumn fQiAlias fcName
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pgFmtJoinCondition :: JoinCondition -> SqlFragment
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pgFmtJoinCondition (JoinCondition (qi, al1, col1) (QualifiedIdentifier schema fTable, al2, col2)) =
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pgFmtColumn (fromMaybe qi $ aliasToQi al1) col1 <> " = " <>
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pgFmtColumn (fromMaybe (removeSourceCTESchema schema fTable) $ aliasToQi al2) col2
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where
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aliasToQi al = QualifiedIdentifier "" <$> al
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pgFmtLogicTree :: QualifiedIdentifier -> LogicTree -> SqlFragment
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pgFmtLogicTree qi (Expr hasNot op forest) = notOp <> " (" <> intercalate (" " <> show op <> " ") (pgFmtLogicTree qi <$> forest) <> ")"
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@@ -276,15 +276,17 @@ type SelectItem = (Field, Maybe Cast, Maybe Alias, Maybe RelationDetail)
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-- | Path of the embedded levels, e.g "clients.projects.name=eq.." gives Path ["clients", "projects"]
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type EmbedPath = [Text]
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data Filter = Filter { field::Field, opExpr::OpExpr } deriving (Show, Eq)
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data JoinCond = JoinCond (QualifiedIdentifier, FieldName, Level) (QualifiedIdentifier, FieldName, Level) deriving (Show, Eq)
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type Level = Integer
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data JoinCondition = JoinCondition (QualifiedIdentifier, Maybe Alias, FieldName)
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(QualifiedIdentifier, Maybe Alias, FieldName) deriving (Show, Eq)
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data ReadQuery = Select { select::[SelectItem], from::[TableName], where_::[LogicTree], joinConds::[JoinCond], order::[OrderTerm], range_::NonnegRange } deriving (Show, Eq)
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data ReadQuery = Select { select::[SelectItem], from::[TableName], where_::[LogicTree], joinConditions::[JoinCondition], order::[OrderTerm], range_::NonnegRange } deriving (Show, Eq)
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data MutateQuery = Insert { in_::TableName, insPkCols::[Text], qPayload::PayloadJSON, onConflict:: Maybe PreferResolution, where_::[LogicTree], returning::[FieldName] }
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| Delete { in_::TableName, where_::[LogicTree], returning::[FieldName] }
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| Update { in_::TableName, qPayload::PayloadJSON, where_::[LogicTree], returning::[FieldName] } deriving (Show, Eq)
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type ReadNode = (ReadQuery, (NodeName, Maybe Relation, Maybe Alias, Maybe RelationDetail, Level))
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type ReadNode = (ReadQuery, (NodeName, Maybe Relation, Maybe Alias, Maybe RelationDetail, Depth))
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type ReadRequest = Tree ReadNode
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-- Depth of the ReadRequest tree
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type Depth = Integer
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type MutateRequest = MutateQuery
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data DbRequest = DbRead ReadRequest | DbMutate MutateRequest
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