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Postgres95 1.01 Distribution - Virgin Sources
This commit is contained in:
Marc G. Fournier
255
src/backend/rewrite/rewriteDefine.c
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255
src/backend/rewrite/rewriteDefine.c
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/*-------------------------------------------------------------------------
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*
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* rewriteDefine.c--
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* routines for defining a rewrite rule
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteDefine.c,v 1.1.1.1 1996/07/09 06:21:51 scrappy Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include <stdio.h>
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#include <string.h>
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#include "postgres.h"
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#include "utils/rel.h" /* for Relation stuff */
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#include "access/heapam.h" /* access methods like amopenr */
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#include "utils/builtins.h"
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#include "utils/elog.h" /* for elog */
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#include "utils/palloc.h"
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#include "utils/lsyscache.h" /* for get_typlen */
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#include "nodes/pg_list.h" /* for Lisp support */
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#include "nodes/parsenodes.h"
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#include "parser/catalog_utils.h"
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#include "rewrite/locks.h"
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#include "rewrite/rewriteRemove.h"
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#include "rewrite/rewriteSupport.h"
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#include "tcop/tcopprot.h"
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Oid LastOidProcessed = InvalidOid;
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/*
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* This is too small for many rule plans, but it'll have to do for now.
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* Rule plans, etc will eventually have to be large objects.
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*
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* should this be smaller?
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*/
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#define RULE_PLAN_SIZE 8192
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static void
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strcpyq(char *dest, char *source)
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{
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char *current=source,*destp= dest;
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for(current=source; *current; current++) {
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if (*current == '\"') {
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*destp = '\\';
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destp++;
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}
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*destp = *current;
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destp++;
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}
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*destp = '\0';
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}
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/*
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* InsertRule -
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* takes the arguments and inserts them as attributes into the system
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* relation "pg_rewrite"
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*
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* MODS : changes the value of LastOidProcessed as a side
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* effect of inserting the rule tuple
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*
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* ARGS : rulname - name of the rule
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* evtype - one of RETRIEVE,REPLACE,DELETE,APPEND
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* evobj - name of relation
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* evslot - comma delimited list of slots
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* if null => multi-attr rule
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* evinstead - is an instead rule
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* actiontree - parsetree(s) of rule action
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*/
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static Oid
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InsertRule(char *rulname,
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int evtype,
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char *evobj,
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char *evslot,
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char *evqual,
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bool evinstead,
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char *actiontree)
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{
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static char rulebuf[RULE_PLAN_SIZE];
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static char actionbuf[RULE_PLAN_SIZE];
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static char qualbuf[RULE_PLAN_SIZE];
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Oid eventrel_oid = InvalidOid;
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AttrNumber evslot_index = InvalidAttrNumber;
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Relation eventrel = NULL;
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char *is_instead = "f";
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extern void eval_as_new_xact();
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char *template;
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eventrel = heap_openr(evobj);
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if (eventrel == NULL) {
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elog(WARN, "rules cannot be defined on relations not in schema");
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}
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eventrel_oid = RelationGetRelationId(eventrel);
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/*
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* if the slotname is null, we know that this is a multi-attr
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* rule
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*/
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if (evslot == NULL)
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evslot_index = -1;
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else
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evslot_index = varattno(eventrel, (char*)evslot);
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heap_close(eventrel);
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if (evinstead)
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is_instead = "t";
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if (evqual == NULL)
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evqual = "nil";
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if (IsDefinedRewriteRule(rulname))
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elog(WARN, "Attempt to insert rule '%s' failed: already exists",
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rulname);
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strcpyq(actionbuf,actiontree);
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strcpyq(qualbuf, evqual);
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template = "INSERT INTO pg_rewrite \
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(rulename, ev_type, ev_class, ev_attr, action, ev_qual, is_instead) VALUES \
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('%s', %d::char, %d::oid, %d::int2, '%s'::text, '%s'::text, \
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'%s'::bool);";
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if (strlen(template) + strlen(rulname) + strlen(actionbuf) +
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strlen(qualbuf) + 20 /* fudge fac */ > RULE_PLAN_SIZE) {
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elog(WARN, "DefineQueryRewrite: rule plan string too big.");
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}
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sprintf(rulebuf, template,
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rulname, evtype, eventrel_oid, evslot_index, actionbuf,
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qualbuf, is_instead);
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pg_eval(rulebuf, (char **) NULL, (Oid *) NULL, 0);
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return (LastOidProcessed);
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}
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/*
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* for now, event_object must be a single attribute
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*/
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static void
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ValidateRule(int event_type,
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char *eobj_string,
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char *eslot_string,
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Node *event_qual,
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List **action,
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int is_instead,
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Oid event_attype)
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{
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if (((event_type == CMD_INSERT) || (event_type == CMD_DELETE)) &&
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eslot_string) {
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elog(WARN,
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"rules not allowed for insert or delete events to an attribute");
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}
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if (event_qual && !*action && is_instead)
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elog(WARN,
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"event_quals on 'instead nothing' rules not currently supported");
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#if 0
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/* on retrieve to class.attribute do instead nothing is converted
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* to 'on retrieve to class.attribute do instead
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* retrieve (attribute = NULL)'
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* --- this is also a terrible hack that works well -- glass*/
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if (is_instead && !*action && eslot_string && event_type == CMD_SELECT) {
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char *temp_buffer = (char *) palloc(strlen(template)+80);
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sprintf(temp_buffer, template, event_attype,
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get_typlen(event_attype), eslot_string,
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event_attype);
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*action = (List*) stringToNode(temp_buffer);
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pfree(temp_buffer);
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}
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#endif
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}
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void
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DefineQueryRewrite(RuleStmt *stmt)
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{
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CmdType event_type = stmt->event;
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Attr *event_obj = stmt->object;
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Node *event_qual = stmt->whereClause;
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bool is_instead = stmt->instead;
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List *action = stmt->actions;
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Relation event_relation = NULL ;
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Oid ruleId;
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Oid ev_relid = 0;
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char *eslot_string = NULL;
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int event_attno = 0;
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Oid event_attype = 0;
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char *actionP, *event_qualP;
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extern Oid att_typeid();
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if (event_obj->attrs)
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eslot_string = strVal(lfirst(event_obj->attrs));
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else
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eslot_string = NULL;
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event_relation = heap_openr(event_obj->relname);
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if ( event_relation == NULL ) {
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elog(WARN, "virtual relations not supported yet");
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}
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ev_relid = RelationGetRelationId(event_relation);
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if (eslot_string == NULL) {
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event_attno = -1;
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event_attype = -1; /* XXX - don't care */
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} else {
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event_attno = varattno(event_relation, eslot_string);
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event_attype = att_typeid(event_relation,event_attno);
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}
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heap_close(event_relation);
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/* fix bug about instead nothing */
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ValidateRule(event_type, event_obj->relname,
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eslot_string, event_qual, &action,
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is_instead,event_attype);
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if (action == NULL) {
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if (!is_instead) return; /* doesn't do anything */
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event_qualP = nodeToString(event_qual);
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ruleId = InsertRule(stmt->rulename,
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event_type,
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event_obj->relname,
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eslot_string,
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event_qualP,
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true,
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"nil");
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prs2_addToRelation(ev_relid, ruleId, event_type, event_attno, TRUE,
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event_qual, NIL);
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} else {
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event_qualP = nodeToString(event_qual);
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actionP = nodeToString(action);
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ruleId = InsertRule(stmt->rulename,
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event_type,
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event_obj->relname,
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eslot_string,
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event_qualP,
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is_instead,
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actionP);
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/* what is the max size of type text? XXX -- glass */
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if (length(action) > 15 )
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elog(WARN,"max # of actions exceeded");
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prs2_addToRelation(ev_relid, ruleId, event_type, event_attno,
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is_instead, event_qual, action);
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}
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}
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