From: Jan Wieck <jwieck@debis.com>

Hi,

    as  proposed here comes the first patch for the query rewrite
    system.

  <for details, see archive dated Mon, 17 Aug 1998>

src/backend/parser/analyze.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.79 1998/07/20 20:48:51 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.80 1998/08/18 00:48:54 scrappy Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -742,11 +742,33 @@ static Query *
 transformRuleStmt(ParseState *pstate, RuleStmt *stmt)
 {
 	Query	   *qry;
+	Query	   *action;
 	List	   *actions;
 
 	qry = makeNode(Query);
 	qry->commandType = CMD_UTILITY;
 
+	/*
+	 * 'instead nothing' rules with a qualification need a
+	 * query a rangetable so the rewrite handler can add the
+	 * negated rule qualification to the original query. We
+	 * create a query with the new command type CMD_NOTHING
+	 * here that is treated special by the rewrite system.
+	 */
+	if (stmt->actions == NIL) {
+		Query		*nothing_qry = makeNode(Query);
+		nothing_qry->commandType = CMD_NOTHING;
+
+		addRangeTableEntry(pstate, stmt->object->relname, "*CURRENT*",
+						   FALSE, FALSE);
+		addRangeTableEntry(pstate, stmt->object->relname, "*NEW*",
+						   FALSE, FALSE);
+
+		nothing_qry->rtable = pstate->p_rtable;
+
+		stmt->actions = lappend(NIL, nothing_qry);
+	}
+
 	actions = stmt->actions;
 
 	/*
@@ -768,6 +790,8 @@ transformRuleStmt(ParseState *pstate, RuleStmt *stmt)
 		pstate->p_is_rule = true;		/* for expand all */
 		pstate->p_hasAggs = false;
 
+		action = (Query *)lfirst(actions);
+		if (action->commandType != CMD_NOTHING)
 			lfirst(actions) = transformStmt(pstate, lfirst(actions));
 		actions = lnext(actions);
 	}

src/backend/parser/gram.y

@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.22 1998/08/17 16:08:34 thomas Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.23 1998/08/18 00:48:55 scrappy Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -1955,6 +1955,7 @@ RuleStmt:  CREATE RULE name AS
 OptStmtList:  NOTHING					{ $$ = NIL; }
 		| OptimizableStmt				{ $$ = lcons($1, NIL); }
 		| '[' OptStmtBlock ']'			{ $$ = $2; }
+		| '(' OptStmtBlock ')'			{ $$ = $2; }
 		;
 
 OptStmtBlock:  OptStmtMulti

src/backend/parser/parse_relation.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_relation.c,v 1.12 1998/07/08 14:04:11 thomas Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_relation.c,v 1.13 1998/08/18 00:48:57 scrappy Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -191,9 +191,14 @@ addRangeTableEntry(ParseState *pstate,
 	if (pstate != NULL)
 	{
 		if (refnameRangeTablePosn(pstate, refname, &sublevels_up) != 0 &&
-			(!inFromCl || sublevels_up == 0))
+			(!inFromCl || sublevels_up == 0)) {
+			if (!strcmp(refname, "*CURRENT*") || !strcmp(refname, "*NEW*")) {
+				int	rt_index = refnameRangeTablePosn(pstate, refname, &sublevels_up);
+				return (RangeTblEntry *)nth(rt_index - 1, pstate->p_rtable);
+			}
 			elog(ERROR, "Table name %s specified more than once", refname);
 		}
+	}
 
 	rte->relname = pstrdup(relname);
 	rte->refname = pstrdup(refname);

src/backend/rewrite/rewriteDefine.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteDefine.c,v 1.16 1998/06/15 19:29:06 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteDefine.c,v 1.17 1998/08/18 00:48:58 scrappy Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -155,12 +155,7 @@ ValidateRule(int event_type,
 		"rules not allowed for insert or delete events to an attribute");
 	}
 
-	if (event_qual && !*action && is_instead)
-		elog(ERROR,
-		"event_quals on 'instead nothing' rules not currently supported");
-
 #if 0
-
 	/*
 	 * on retrieve to class.attribute do instead nothing is converted to
 	 * 'on retrieve to class.attribute do instead retrieve (attribute =

src/include/nodes/nodes.h

@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: nodes.h,v 1.26 1998/08/05 04:49:12 scrappy Exp $
+ * $Id: nodes.h,v 1.27 1998/08/18 00:49:01 scrappy Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -305,8 +305,12 @@ typedef enum CmdType
 	CMD_INSERT,					/* insert stmt (formerly append) */
 	CMD_DELETE,
 	CMD_NOTIFY,
-	CMD_UTILITY					/* cmds like create, destroy, copy,
+	CMD_UTILITY,					/* cmds like create, destroy, copy,
 								 * vacuum, etc. */
+	CMD_NOTHING					/* dummy command for
+							 * instead nothing
+							 * rules with qual
+							 */
 } CmdType;
 
 

src/test/regress/expected/setup_ruletest.out

+QUERY: create table rtest_t1 (a int4, b int4);
+QUERY: create table rtest_t2 (a int4, b int4);
+QUERY: create table rtest_t3 (a int4, b int4);
+QUERY: create view rtest_v1 as select * from rtest_t1;
+QUERY: create rule rtest_v1_ins as on insert to rtest_v1 do instead
+	insert into rtest_t1 values (new.a, new.b);
+QUERY: create rule rtest_v1_upd as on update to rtest_v1 do instead
+	update rtest_t1 set a = new.a, b = new.b
+	where a = current.a;
+QUERY: create rule rtest_v1_del as on delete to rtest_v1 do instead
+	delete from rtest_t1 where a = current.a;
+QUERY: create table rtest_system (sysname text, sysdesc text);
+QUERY: create table rtest_interface (sysname text, ifname text);
+QUERY: create table rtest_person (pname text, pdesc text);
+QUERY: create table rtest_admin (pname text, sysname text);
+QUERY: create rule rtest_sys_upd1 as on update to rtest_system do
+	update rtest_interface set sysname = new.sysname
+		where sysname = current.sysname;
+QUERY: create rule rtest_sys_upd2 as on update to rtest_system do
+	update rtest_admin set sysname = new.sysname
+		where sysname = current.sysname;
+QUERY: create rule rtest_sys_del1 as on delete to rtest_system do
+	delete from rtest_interface where sysname = current.sysname;
+QUERY: create rule rtest_sys_del2 as on delete to rtest_system do
+	delete from rtest_admin where sysname = current.sysname;
+QUERY: create rule rtest_pers_upd as on update to rtest_person do
+	update rtest_admin set pname = new.pname where pname = current.pname;
+QUERY: create rule rtest_pers_del as on delete to rtest_person do
+	delete from rtest_admin where pname = current.pname;
+QUERY: create table rtest_emp (ename char(20), salary money);
+QUERY: create table rtest_emplog (ename char(20), who name, action char(10), newsal money, oldsal money);
+QUERY: create table rtest_empmass (ename char(20), salary money);
+QUERY: create rule rtest_emp_ins as on insert to rtest_emp do
+	insert into rtest_emplog values (new.ename, getpgusername(),
+			'hired', new.salary, '0.00');
+QUERY: create rule rtest_emp_upd as on update to rtest_emp where new.salary != current.salary do
+	insert into rtest_emplog values (new.ename, getpgusername(),
+			'honored', new.salary, current.salary);
+QUERY: create rule rtest_emp_del as on delete to rtest_emp do
+	insert into rtest_emplog values (current.ename, getpgusername(),
+			'fired', '0.00', current.salary);
+QUERY: create table rtest_t4 (a int4, b text);
+QUERY: create table rtest_t5 (a int4, b text);
+QUERY: create table rtest_t6 (a int4, b text);
+QUERY: create table rtest_t7 (a int4, b text);
+QUERY: create table rtest_t8 (a int4, b text);
+QUERY: create table rtest_t9 (a int4, b text);
+QUERY: create rule rtest_t4_ins1 as on insert to rtest_t4
+		where new.a >= 10 and new.a < 20 do instead
+	insert into rtest_t5 values (new.a, new.b);
+QUERY: create rule rtest_t4_ins2 as on insert to rtest_t4
+		where new.a >= 20 and new.a < 30 do
+	insert into rtest_t6 values (new.a, new.b);
+QUERY: create rule rtest_t5_ins as on insert to rtest_t5
+		where new.a > 15 do
+	insert into rtest_t7 values (new.a, new.b);
+QUERY: create rule rtest_t6_ins as on insert to rtest_t6
+		where new.a > 25 do instead
+	insert into rtest_t8 values (new.a, new.b);
+QUERY: create table rtest_order1 (a int4);
+QUERY: create table rtest_order2 (a int4, b int4, c text);
+QUERY: create sequence rtest_seq;
+QUERY: create rule rtest_order_r3 as on insert to rtest_order1 do instead
+	insert into rtest_order2 values (new.a, nextval('rtest_seq'),
+		'rule 3 - this should run 3rd or 4th');
+QUERY: create rule rtest_order_r4 as on insert to rtest_order1
+		where a < 100 do instead
+	insert into rtest_order2 values (new.a, nextval('rtest_seq'),
+		'rule 4 - this should run 2nd');
+QUERY: create rule rtest_order_r2 as on insert to rtest_order1 do
+	insert into rtest_order2 values (new.a, nextval('rtest_seq'),
+		'rule 2 - this should run 1st');
+QUERY: create rule rtest_order_r1 as on insert to rtest_order1 do instead
+	insert into rtest_order2 values (new.a, nextval('rtest_seq'),
+		'rule 1 - this should run 3rd or 4th');
+QUERY: create table rtest_nothn1 (a int4, b text);
+QUERY: create table rtest_nothn2 (a int4, b text);
+QUERY: create table rtest_nothn3 (a int4, b text);
+QUERY: create table rtest_nothn4 (a int4, b text);
+QUERY: create rule rtest_nothn_r1 as on insert to rtest_nothn1
+	where new.a >= 10 and new.a < 20 do instead (select 1);
+QUERY: create rule rtest_nothn_r2 as on insert to rtest_nothn1
+	where new.a >= 30 and new.a < 40 do instead nothing;
+QUERY: create rule rtest_nothn_r3 as on insert to rtest_nothn2
+	where new.a >= 100 do instead
+	insert into rtest_nothn3 values (new.a, new.b);
+QUERY: create rule rtest_nothn_r4 as on insert to rtest_nothn2
+	do instead nothing;