database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-08-21 10:42:50 +03:00
Code Activity

Disallow LATERAL references to the target table of an UPDATE/DELETE.

Browse Source 
On second thought, commit 0c051c9008 was
over-hasty: rather than allowing this case, we ought to reject it for now.
That leaves the field clear for a future feature that allows the target
table to be re-specified in the FROM (or USING) clause, which will enable
left-joining the target table to something else.  We can then also allow
LATERAL references to such an explicitly re-specified target table.
But allowing them right now will create ambiguities or worse for such a
feature, and it isn't something we documented 9.3 as supporting.

While at it, add a convenience subroutine to avoid having several copies
of the ereport for disalllowed-LATERAL-reference cases.
This commit is contained in:
Tom Lane
2014-01-11 19:03:12 -05:00
parent 910bac5953
commit 158b7fa6a3
5 changed files with 72 additions and 66 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
src/backend/parser/analyze.c
View File

@@ -367,8 +367,9 @@ transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt)
/* there's no DISTINCT in DELETE */
qry->distinctClause = NIL;
/* subqueries in USING can see the result relation only via LATERAL */
/* subqueries in USING cannot access the result relation */
nsitem->p_lateral_only = true;
nsitem->p_lateral_ok = false;
/*
* The USING clause is non-standard SQL syntax, and is equivalent in
@@ -378,8 +379,9 @@ transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt)
*/
transformFromClause(pstate, stmt->usingClause);
/* remaining clauses can see the result relation normally */
/* remaining clauses can reference the result relation normally */
nsitem->p_lateral_only = false;
nsitem->p_lateral_ok = true;
qual = transformWhereClause(pstate, stmt->whereClause,
EXPR_KIND_WHERE, "WHERE");
@@ -1925,8 +1927,9 @@ transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt)
/* grab the namespace item made by setTargetTable */
nsitem = (ParseNamespaceItem *) llast(pstate->p_namespace);
/* subqueries in FROM can see the result relation only via LATERAL */
/* subqueries in FROM cannot access the result relation */
nsitem->p_lateral_only = true;
nsitem->p_lateral_ok = false;
/*
* the FROM clause is non-standard SQL syntax. We used to be able to do
@@ -1934,8 +1937,9 @@ transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt)
*/
transformFromClause(pstate, stmt->fromClause);
/* remaining clauses can see the result relation normally */
/* remaining clauses can reference the result relation normally */
nsitem->p_lateral_only = false;
nsitem->p_lateral_ok = true;
qry->targetList = transformTargetList(pstate, stmt->targetList,
EXPR_KIND_UPDATE_SOURCE);