Support assignment to subfields of composite columns in UPDATE and INSERT.

As a side effect, cause subscripts in INSERT targetlists to do something
more or less sensible; previously we evaluated such subscripts and then
effectively ignored them.  Another side effect is that UPDATE-ing an
element or slice of an array value that is NULL now produces a non-null
result, namely an array containing just the assigned-to positions.

1 files changed, 32 insertions, 1 deletions

diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c
index b22360ac2b1..a3a2ddfbd83 100644
--- a/src/backend/optimizer/util/clauses.c
+++ b/src/backend/optimizer/util/clauses.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.174 2004/06/05 19:48:08 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.175 2004/06/09 19:08:16 tgl Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -724,6 +724,13 @@ contain_nonstrict_functions_walker(Node *node, void *context)
 		/* an aggregate could return non-null with null input */
 		return true;
 	}
+	if (IsA(node, ArrayRef))
+	{
+		/* array assignment is nonstrict */
+		if (((ArrayRef *) node)->refassgnexpr != NULL)
+			return true;
+		/* else fall through to check args */
+	}
 	if (IsA(node, FuncExpr))
 	{
 		FuncExpr   *expr = (FuncExpr *) node;
@@ -771,6 +778,8 @@ contain_nonstrict_functions_walker(Node *node, void *context)
 	}
 	if (IsA(node, SubPlan))
 		return true;
+	if (IsA(node, FieldStore))
+		return true;
 	if (IsA(node, CaseExpr))
 		return true;
 	if (IsA(node, CaseWhen))
@@ -2450,6 +2459,16 @@ expression_tree_walker(Node *node,
 			break;
 		case T_FieldSelect:
 			return walker(((FieldSelect *) node)->arg, context);
+		case T_FieldStore:
+			{
+				FieldStore   *fstore = (FieldStore *) node;
+
+				if (walker(fstore->arg, context))
+					return true;
+				if (walker(fstore->newvals, context))
+					return true;
+			}
+			break;
 		case T_RelabelType:
 			return walker(((RelabelType *) node)->arg, context);
 		case T_CaseExpr:
@@ -2840,6 +2859,18 @@ expression_tree_mutator(Node *node,
 				return (Node *) newnode;
 			}
 			break;
+		case T_FieldStore:
+			{
+				FieldStore *fstore = (FieldStore *) node;
+				FieldStore *newnode;
+
+				FLATCOPY(newnode, fstore, FieldStore);
+				MUTATE(newnode->arg, fstore->arg, Expr *);
+				MUTATE(newnode->newvals, fstore->newvals, List *);
+				newnode->fieldnums = list_copy(fstore->fieldnums);
+				return (Node *) newnode;
+			}
+			break;
 		case T_RelabelType:
 			{
 				RelabelType *relabel = (RelabelType *) node;