Add implicitJoins to ReadQuery type

src/PostgREST/DbRequestBuilder.hs

@@ -68,7 +68,7 @@ readRequest maxRows allRels proc apiRequest  =
     buildReadRequest fieldTree =
       let rootDepth = 0
           rootNodeName = if action == ActionRead then rootTableName else sourceCTEName in
-      foldr (treeEntry rootDepth) (Node (Select [] [rootNodeName] [] [] [] allRange, (rootNodeName, Nothing, Nothing, Nothing, rootDepth)) []) fieldTree
+      foldr (treeEntry rootDepth) (Node (Select [] rootNodeName [] [] [] [] allRange, (rootNodeName, Nothing, Nothing, Nothing, rootDepth)) []) fieldTree
       where
         treeEntry :: Depth -> Tree SelectItem -> ReadRequest -> ReadRequest
         treeEntry depth (Node fld@((fn, _),_,alias,relationDetail) fldForest) (Node (q, i) rForest) =
@@ -76,7 +76,7 @@ readRequest maxRows allRels proc apiRequest  =
           case fldForest of
             [] -> Node (q {select=fld:select q}, i) rForest
             _  -> Node (q, i) $
-                  foldr (treeEntry nxtDepth) (Node (Select [] [fn] [] [] [] allRange, (fn, Nothing, alias, relationDetail, nxtDepth)) []) fldForest:rForest
+                  foldr (treeEntry nxtDepth) (Node (Select [] fn [] [] [] [] allRange, (fn, Nothing, alias, relationDetail, nxtDepth)) []) fldForest:rForest
 
     relations :: [Relation]
     relations = case action of
@@ -111,10 +111,10 @@ augumentRequestWithJoin schema allRels request =
   >>= addJoinConditions schema
 
 addRelations :: Schema -> [Relation] -> Maybe ReadRequest -> ReadRequest -> Either ApiRequestError ReadRequest
-addRelations schema allRelations parentNode (Node (query, (nodeName, _, alias, relationDetail, depth)) forest) =
+addRelations schema allRelations parentNode (Node (query@Select{from=tbl}, (nodeName, _, alias, relationDetail, depth)) forest) =
   case parentNode of
-    Just (Node (Select{from=[parentNodeTable]}, _) _) ->
-      let newFrom r = (\tName -> if tName == nodeName then tableName (relTable r) else tName) <$> from query
+    Just (Node (Select{from=parentNodeTable}, _) _) ->
+      let newFrom r = if tbl == nodeName then tableName (relTable r) else tbl
           newReadNode = (\r -> (query{from=newFrom r}, (nodeName, Just r, alias, Nothing, depth))) <$> rel
           rel :: Either ApiRequestError Relation
           rel = note (NoRelationBetween parentNodeTable nodeName) $
@@ -216,7 +216,7 @@ addJoinConditions schema (Node node@(query, nodeProps@(_, relation, _, _, _)) fo
     Just rel@Relation{relType=Child} -> Node (augmentQuery rel, nodeProps) <$> updatedForest
     Just rel@Relation{relType=Many, relLinkTable=(Just linkTable)} ->
       let rq = augmentQuery rel in
-      Node (rq{from=tableName linkTable:from rq}, nodeProps) <$> updatedForest
+      Node (rq{implicitJoins=tableName linkTable:implicitJoins rq}, nodeProps) <$> updatedForest
     _ -> Left UnknownRelation
   where
     updatedForest = mapM (addJoinConditions schema) forest

src/PostgREST/QueryBuilder.hs

@@ -219,7 +219,7 @@ requestToCountQuery schema (DbRead (Node (Select{where_=logicForest}, (mainTbl,
    qi = removeSourceCTESchema schema mainTbl
 
 requestToQuery :: Schema -> Bool -> DbRequest -> SqlQuery
-requestToQuery schema isParent (DbRead (Node (Select colSelects tbls logicForest joinConditions_ ordts range, (nodeName, maybeRelation, _, _, depth)) forest)) =
+requestToQuery schema isParent (DbRead (Node (Select colSelects tbl implJoins logicForest joinConditions_ ordts range, (_, maybeRelation, _, _, depth)) forest)) =
   unwords [
     "SELECT " <> intercalate ", " (map (pgFmtSelectItem qi) colSelects ++ selects),
     "FROM " <> intercalate ", " tables,
@@ -230,19 +230,19 @@ requestToQuery schema isParent (DbRead (Node (Select colSelects tbls logicForest
     ("LIMIT " <> maybe "ALL" show (rangeLimit range) <> " OFFSET " <> show (rangeOffset range)) `emptyOnFalse` (isParent || range == allRange) ]
 
   where
-    mainTbl = maybe nodeName (tableName . relTable) maybeRelation
+    tbls = tbl:implJoins
     isSelfJoin = maybe False (\r -> relType r /= Root && relTable r == relFTable r) maybeRelation
     (qi, tables, joinConds) =
       let depthAlias name dpth = if dpth /= 0  then name <> "_" <> show dpth else name in -- Root node doesn't get aliased
       if isSelfJoin
         then (
-          QualifiedIdentifier "" (depthAlias mainTbl depth),
+          QualifiedIdentifier "" (depthAlias tbl depth),
           (\t -> fromQi (removeSourceCTESchema schema t) <> " AS " <> pgFmtIdent (depthAlias t depth)) <$> tbls,
           (\(JoinCondition (qi1, _, c1) (qi2, _, c2)) ->
             JoinCondition (qi1, Just $ depthAlias (qiName qi1) depth, c1)
                           (qi2, Just $ depthAlias (qiName qi2) (depth - 1), c2)) <$> joinConditions_)
         else (
-          removeSourceCTESchema schema mainTbl,
+          removeSourceCTESchema schema tbl,
           fromQi . removeSourceCTESchema schema <$> tbls,
           joinConditions_)
 

src/PostgREST/Types.hs

@@ -308,7 +308,9 @@ data JoinCondition = JoinCondition (QualifiedIdentifier, Maybe Alias, FieldName)
 
 data ReadQuery = Select {
     select         :: [SelectItem]
-  , from           :: [TableName]
+  , from           :: TableName
+-- | Only used for many to many joins. Parent and Child joins use explicit joins.
+  , implicitJoins  :: [TableName]
   , where_         :: [LogicTree]
   , joinConditions :: [JoinCondition]
   , order          :: [OrderTerm]