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Only alias tables on self join cases

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steve-chavez
2018-04-02 11:09:45 -05:00
committed by Steve Chávez
parent 243e692192
commit edae60f8c1
3 changed files with 70 additions and 62 deletions
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src/PostgREST/QueryBuilder.hs
+30 -17
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@@ -218,20 +218,32 @@ 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 joinConds_ ordts range, (nodeName, maybeRelation, _, _, level)) forest)) =
query
requestToQuery schema isParent (DbRead (Node (Select colSelects tbls logicForest joinConditions_ ordts range, (nodeName, maybeRelation, _, _, depth)) forest)) =
unwords [
"SELECT " <> intercalate ", " (map (pgFmtSelectItem qi) colSelects ++ selects),
"FROM " <> intercalate ", " tables,
unwords joins,
("WHERE " <> intercalate " AND " (map (pgFmtLogicTree qi) logicForest ++ map pgFmtJoinCondition joinConds))
`emptyOnFalse` (null logicForest && null joinConds),
("ORDER BY " <> intercalate ", " (map (pgFmtOrderTerm qi) ordts)) `emptyOnFalse` null ordts,
("LIMIT " <> maybe "ALL" show (rangeLimit range) <> " OFFSET " <> show (rangeOffset range)) `emptyOnFalse` (isParent || range == allRange) ]
where
mainTbl = fromMaybe nodeName (tableName . relTable <$> maybeRelation)
tableAlias tbl = tbl <> "_" <> show level
qi = QualifiedIdentifier "" $ tableAlias mainTbl
query = unwords [
"SELECT " <> intercalate ", " (map (pgFmtSelectItem qi) colSelects ++ selects),
"FROM " <> intercalate ", " (map (\t -> fromQi (removeSourceCTESchema schema t) <> " AS " <> pgFmtIdent (tableAlias t)) tbls),
unwords joins,
("WHERE " <> intercalate " AND " (map (pgFmtLogicTree qi) logicForest ++ map pgFmtJoinCond joinConds_))
`emptyOnFalse` (null logicForest && null joinConds_),
("ORDER BY " <> intercalate ", " (map (pgFmtOrderTerm qi) ordts)) `emptyOnFalse` null ordts,
("LIMIT " <> maybe "ALL" show (rangeLimit range) <> " OFFSET " <> show (rangeOffset range)) `emptyOnFalse` (isParent || range == allRange) ]
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),
(\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)) <$> joinConditions_)
else (
removeSourceCTESchema schema mainTbl,
fromQi . removeSourceCTESchema schema <$> tbls,
joinConditions_)
(joins, selects) = foldr getQueryParts ([],[]) forest
@@ -423,11 +435,12 @@ pgFmtFilter table (Filter fld (OpExpr hasNot oper)) = notOp <> " " <> case oper
(toS (pgFmtLit v) <> "::unknown ")
(find ((==) . toLower $ v) ["null","true","false"])
pgFmtJoinCond :: JoinCond -> SqlFragment
pgFmtJoinCond (JoinCond (qi, cName, lvl) (fQi, fcName, fLvl)) =
let qiAlias = QualifiedIdentifier "" (qiName qi <> "_" <> show lvl)
fQiAlias = QualifiedIdentifier "" (qiName fQi <> "_" <> show fLvl) in
pgFmtColumn qiAlias cName <> " = " <> pgFmtColumn fQiAlias fcName
pgFmtJoinCondition :: JoinCondition -> SqlFragment
pgFmtJoinCondition (JoinCondition (qi, al1, col1) (QualifiedIdentifier schema fTable, al2, col2)) =
pgFmtColumn (fromMaybe qi $ aliasToQi al1) col1 <> " = " <>
pgFmtColumn (fromMaybe (removeSourceCTESchema schema fTable) $ aliasToQi al2) col2
where
aliasToQi al = QualifiedIdentifier "" <$> al
pgFmtLogicTree :: QualifiedIdentifier -> LogicTree -> SqlFragment
pgFmtLogicTree qi (Expr hasNot op forest) = notOp <> " (" <> intercalate (" " <> show op <> " ") (pgFmtLogicTree qi <$> forest) <> ")"