* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/optimizer/prep/preptlist.c,v 1.36 2000/04/12 17:15:23 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/optimizer/prep/preptlist.c,v 1.37 2000/07/22 06:19:04 tgl Exp $
*
*-------------------------------------------------------------------------
*/
static List *expand_targetlist(List *tlist, int command_type,
Index result_relation, List *range_table);
+static TargetEntry *process_matched_tle(TargetEntry *src_tle,
+ TargetEntry *prior_tle,
+ int attrno);
/*
List *temp;
/*
- * Keep a map of which tlist items we have transferred to new list. +1
- * here keeps palloc from complaining if old_tlist_len=0.
+ * Keep a map of which tlist items we have transferred to new list.
+ *
+ * +1 here just keeps palloc from complaining if old_tlist_len==0.
*/
tlistentry_used = (bool *) palloc((old_tlist_len + 1) * sizeof(bool));
memset(tlistentry_used, 0, (old_tlist_len + 1) * sizeof(bool));
/*
* We match targetlist entries to attributes using the resname.
+ * Junk attributes are not candidates to be matched.
*/
old_tlist_index = 0;
foreach(temp, tlist)
Resdom *resdom = old_tle->resdom;
if (!tlistentry_used[old_tlist_index] &&
- strcmp(resdom->resname, attrname) == 0 &&
- !resdom->resjunk)
+ !resdom->resjunk &&
+ strcmp(resdom->resname, attrname) == 0)
{
-
- /*
- * We can recycle the old TLE+resdom if right resno; else
- * make a new one to avoid modifying the old tlist
- * structure. (Is preserving old tlist actually
- * necessary?)
- */
- if (resdom->resno == attrno)
- new_tle = old_tle;
- else
- {
- resdom = (Resdom *) copyObject((Node *) resdom);
- resdom->resno = attrno;
- new_tle = makeTargetEntry(resdom, old_tle->expr);
- }
+ new_tle = process_matched_tle(old_tle, new_tle, attrno);
tlistentry_used[old_tlist_index] = true;
- break;
}
old_tlist_index++;
}
{
case CMD_INSERT:
{
-#ifdef _DROP_COLUMN_HACK__
- Datum typedefault;
-
-#else
Datum typedefault = get_typdefault(atttype);
-
-#endif /* _DROP_COLUMN_HACK__ */
int typlen;
Const *temp_const;
#ifdef _DROP_COLUMN_HACK__
if (COLUMN_IS_DROPPED(att_tup))
typedefault = PointerGetDatum(NULL);
- else
- typedefault = get_typdefault(atttype);
#endif /* _DROP_COLUMN_HACK__ */
+
if (typedefault == PointerGetDatum(NULL))
typlen = 0;
else
Var *temp_var;
#ifdef _DROP_COLUMN_HACK__
- Node *temp_node = (Node *) NULL;
-
if (COLUMN_IS_DROPPED(att_tup))
{
- temp_node = (Node *) makeConst(atttype, 0,
+ temp_var = (Var *) makeConst(atttype, 0,
PointerGetDatum(NULL),
true,
false,
}
else
#endif /* _DROP_COLUMN_HACK__ */
- temp_var = makeVar(result_relation, attrno, atttype,
- atttypmod, 0);
-#ifdef _DROP_COLUMN_HACK__
- if (!temp_node)
- temp_node = (Node *) temp_var;
-#endif /* _DROP_COLUMN_HACK__ */
+ temp_var = makeVar(result_relation,
+ attrno,
+ atttype,
+ atttypmod,
+ 0);
new_tle = makeTargetEntry(makeResdom(attrno,
atttype,
atttypmod,
- pstrdup(attrname),
+ pstrdup(attrname),
0,
(Oid) 0,
false),
-#ifdef _DROP_COLUMN_HACK__
- temp_node);
-#else
(Node *) temp_var);
-#endif /* _DROP_COLUMN_HACK__ */
break;
}
default:
if (!tlistentry_used[old_tlist_index])
{
- Resdom *resdom;
+ Resdom *resdom = old_tle->resdom;
- resdom = (Resdom *) copyObject((Node *) old_tle->resdom);
- resdom->resno = attrno++;
- resdom->resjunk = true;
- new_tlist = lappend(new_tlist,
- makeTargetEntry(resdom, old_tle->expr));
+ if (! resdom->resjunk)
+ elog(ERROR, "Unexpected assignment to attribute \"%s\"",
+ resdom->resname);
+ /* Get the resno right, but don't copy unnecessarily */
+ if (resdom->resno != attrno)
+ {
+ resdom = (Resdom *) copyObject((Node *) resdom);
+ resdom->resno = attrno;
+ old_tle = makeTargetEntry(resdom, old_tle->expr);
+ }
+ new_tlist = lappend(new_tlist, old_tle);
+ attrno++;
}
old_tlist_index++;
}
return new_tlist;
}
+
+
+/*
+ * Convert a matched TLE from the original tlist into a correct new TLE.
+ *
+ * This routine checks for multiple assignments to the same target attribute,
+ * such as "UPDATE table SET foo = 42, foo = 43". This is OK only if they
+ * are array assignments, ie, "UPDATE table SET foo[2] = 42, foo[4] = 43".
+ * If so, we need to merge the operations into a single assignment op.
+ * Essentially, the expression we want to produce in this case is like
+ * foo = array_set(array_set(foo, 2, 42), 4, 43)
+ */
+static TargetEntry *process_matched_tle(TargetEntry *src_tle,
+ TargetEntry *prior_tle,
+ int attrno)
+{
+ Resdom *resdom = src_tle->resdom;
+ Node *priorbottom;
+ ArrayRef *newexpr;
+
+ if (prior_tle == NULL)
+ {
+ /*
+ * Normal case where this is the first assignment to the attribute.
+ *
+ * We can recycle the old TLE+resdom if right resno; else make a
+ * new one to avoid modifying the old tlist structure. (Is preserving
+ * old tlist actually necessary? Not sure, be safe.)
+ */
+ if (resdom->resno == attrno)
+ return src_tle;
+ resdom = (Resdom *) copyObject((Node *) resdom);
+ resdom->resno = attrno;
+ return makeTargetEntry(resdom, src_tle->expr);
+ }
+
+ /*
+ * Multiple assignments to same attribute. Allow only if all are
+ * array-assign operators with same bottom array object.
+ */
+ if (src_tle->expr == NULL || !IsA(src_tle->expr, ArrayRef) ||
+ ((ArrayRef *) src_tle->expr)->refassgnexpr == NULL ||
+ prior_tle->expr == NULL || !IsA(prior_tle->expr, ArrayRef) ||
+ ((ArrayRef *) prior_tle->expr)->refassgnexpr == NULL ||
+ ((ArrayRef *) src_tle->expr)->refelemtype !=
+ ((ArrayRef *) prior_tle->expr)->refelemtype)
+ elog(ERROR, "Multiple assignments to same attribute \"%s\"",
+ resdom->resname);
+ /*
+ * Prior TLE could be a nest of ArrayRefs if we do this more than once.
+ */
+ priorbottom = ((ArrayRef *) prior_tle->expr)->refexpr;
+ while (priorbottom != NULL && IsA(priorbottom, ArrayRef) &&
+ ((ArrayRef *) priorbottom)->refassgnexpr != NULL)
+ priorbottom = ((ArrayRef *) priorbottom)->refexpr;
+ if (! equal(priorbottom, ((ArrayRef *) src_tle->expr)->refexpr))
+ elog(ERROR, "Multiple assignments to same attribute \"%s\"",
+ resdom->resname);
+ /*
+ * Looks OK to nest 'em.
+ */
+ newexpr = makeNode(ArrayRef);
+ memcpy(newexpr, src_tle->expr, sizeof(ArrayRef));
+ newexpr->refexpr = prior_tle->expr;
+
+ resdom = (Resdom *) copyObject((Node *) resdom);
+ resdom->resno = attrno;
+ return makeTargetEntry(resdom, (Node *) newexpr);
+}
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