* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $Id: view.c,v 1.68 2002/08/30 19:23:19 tgl Exp $
+ *
+ * IDENTIFICATION
+ * $Header: /cvsroot/pgsql/src/backend/commands/view.c,v 1.69 2002/09/02 02:13:01 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
-#include "access/xact.h"
+#include "access/heapam.h"
#include "catalog/dependency.h"
-#include "catalog/heap.h"
#include "catalog/namespace.h"
#include "commands/tablecmds.h"
#include "commands/view.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "parser/parse_relation.h"
-#include "parser/parse_type.h"
#include "rewrite/rewriteDefine.h"
#include "rewrite/rewriteManip.h"
-#include "rewrite/rewriteRemove.h"
#include "rewrite/rewriteSupport.h"
-#include "utils/syscache.h"
+#include "utils/acl.h"
+#include "utils/lsyscache.h"
/*---------------------------------------------------------------------
* DefineVirtualRelation
*
- * Create the "view" relation.
- * `DefineRelation' does all the work, we just provide the correct
- * arguments!
- *
- * If the relation already exists, then 'DefineRelation' will abort
- * the xact...
+ * Create the "view" relation. `DefineRelation' does all the work,
+ * we just provide the correct arguments ... at least when we're
+ * creating a view. If we're updating an existing view, we have to
+ * work harder.
*---------------------------------------------------------------------
*/
static Oid
-DefineVirtualRelation(const RangeVar *relation, List *tlist)
+DefineVirtualRelation(const RangeVar *relation, List *tlist, bool replace)
{
+ Oid viewOid,
+ namespaceId;
CreateStmt *createStmt = makeNode(CreateStmt);
List *attrList,
*t;
* the (non-junk) targetlist items from the view's SELECT list.
*/
attrList = NIL;
- foreach(t, tlist)
+ foreach (t, tlist)
{
TargetEntry *entry = lfirst(t);
Resdom *res = entry->resdom;
elog(ERROR, "attempted to define virtual relation with no attrs");
/*
- * now create the parameters for keys/inheritance etc. All of them are
- * nil...
+ * Check to see if we want to replace an existing view.
*/
- createStmt->relation = (RangeVar *) relation;
- createStmt->tableElts = attrList;
- createStmt->inhRelations = NIL;
- createStmt->constraints = NIL;
- createStmt->hasoids = false;
+ namespaceId = RangeVarGetCreationNamespace(relation);
+ viewOid = get_relname_relid(relation->relname, namespaceId);
- /*
- * finally create the relation...
- */
- return DefineRelation(createStmt, RELKIND_VIEW);
+ if (OidIsValid(viewOid) && replace)
+ {
+ Relation rel;
+ TupleDesc descriptor;
+
+ /*
+ * Yes. Get exclusive lock on the existing view ...
+ */
+ rel = relation_open(viewOid, AccessExclusiveLock);
+
+ /*
+ * Make sure it *is* a view, and do permissions checks.
+ */
+ if (rel->rd_rel->relkind != RELKIND_VIEW)
+ elog(ERROR, "%s is not a view",
+ RelationGetRelationName(rel));
+
+ if (!pg_class_ownercheck(viewOid, GetUserId()))
+ aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));
+
+ /*
+ * Create a tuple descriptor to compare against the existing view,
+ * and verify it matches.
+ *
+ * XXX the error message is a bit cheesy here: would be useful to
+ * give a more specific complaint about the difference in the
+ * descriptors. No time for it at the moment though.
+ */
+ descriptor = BuildDescForRelation(attrList);
+ if (!equalTupleDescs(descriptor, rel->rd_att))
+ elog(ERROR, "Cannot change column set of existing view %s",
+ RelationGetRelationName(rel));
+
+ /*
+ * Seems okay, so return the OID of the pre-existing view.
+ */
+ relation_close(rel, NoLock); /* keep the lock! */
+
+ return viewOid;
+ }
+ else
+ {
+ /*
+ * now create the parameters for keys/inheritance etc. All of them are
+ * nil...
+ */
+ createStmt->relation = (RangeVar *) relation;
+ createStmt->tableElts = attrList;
+ createStmt->inhRelations = NIL;
+ createStmt->constraints = NIL;
+ createStmt->hasoids = false;
+
+ /*
+ * finally create the relation (this will error out if there's
+ * an existing view, so we don't need more code to complain
+ * if "replace" is false).
+ */
+ return DefineRelation(createStmt, RELKIND_VIEW);
+ }
}
static RuleStmt *
-FormViewRetrieveRule(const RangeVar *view, Query *viewParse)
+FormViewRetrieveRule(const RangeVar *view, Query *viewParse, bool replace)
{
RuleStmt *rule;
rule->event = CMD_SELECT;
rule->instead = true;
rule->actions = makeList1(viewParse);
+ rule->replace = replace;
return rule;
}
static void
-DefineViewRules(const RangeVar *view, Query *viewParse)
+DefineViewRules(const RangeVar *view, Query *viewParse, bool replace)
{
RuleStmt *retrieve_rule;
RuleStmt *delete_rule;
#endif
- retrieve_rule = FormViewRetrieveRule(view, viewParse);
+ retrieve_rule = FormViewRetrieveRule(view, viewParse, replace);
#ifdef NOTYET
-
replace_rule = FormViewReplaceRule(view, viewParse);
append_rule = FormViewAppendRule(view, viewParse);
delete_rule = FormViewDeleteRule(view, viewParse);
*-------------------------------------------------------------------
*/
void
-DefineView(const RangeVar *view, Query *viewParse)
+DefineView(const RangeVar *view, Query *viewParse, bool replace)
{
Oid viewOid;
/*
* Create the view relation
*
- * NOTE: if it already exists, the xact will be aborted.
+ * NOTE: if it already exists and replace is false, the xact will
+ * be aborted.
*/
- viewOid = DefineVirtualRelation(view, viewParse->targetList);
+
+ viewOid = DefineVirtualRelation(view, viewParse->targetList, replace);
/*
* The relation we have just created is not visible to any other
/*
* Now create the rules associated with the view.
*/
- DefineViewRules(view, viewParse);
+ DefineViewRules(view, viewParse, replace);
}
/*
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.209 2002/08/31 22:10:43 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.210 2002/09/02 02:13:01 tgl Exp $
*
*-------------------------------------------------------------------------
*/
Node_Copy(from, newnode, whereClause);
newnode->event = from->event;
newnode->instead = from->instead;
+ newnode->replace = from->replace;
Node_Copy(from, newnode, actions);
return newnode;
Node_Copy(from, newnode, view);
Node_Copy(from, newnode, aliases);
Node_Copy(from, newnode, query);
+ newnode->replace = from->replace;
return newnode;
}
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/nodes/equalfuncs.c,v 1.157 2002/08/31 22:10:43 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/nodes/equalfuncs.c,v 1.158 2002/09/02 02:13:01 tgl Exp $
*
*-------------------------------------------------------------------------
*/
return false;
if (a->instead != b->instead)
return false;
+ if (a->replace != b->replace)
+ return false;
if (!equal(a->actions, b->actions))
return false;
return false;
if (!equal(a->query, b->query))
return false;
+ if (a->replace != b->replace)
+ return false;
return true;
}
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.364 2002/08/29 00:17:04 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.365 2002/09/02 02:13:01 tgl Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
*
*****************************************************************************/
-RuleStmt: CREATE RULE name AS
+RuleStmt: CREATE opt_or_replace RULE name AS
{ QueryIsRule=TRUE; }
ON event TO qualified_name where_clause
DO opt_instead RuleActionList
{
RuleStmt *n = makeNode(RuleStmt);
- n->relation = $9;
- n->rulename = $3;
- n->whereClause = $10;
- n->event = $7;
- n->instead = $12;
- n->actions = $13;
+ n->replace = $2;
+ n->relation = $10;
+ n->rulename = $4;
+ n->whereClause = $11;
+ n->event = $8;
+ n->instead = $13;
+ n->actions = $14;
$$ = (Node *)n;
QueryIsRule=FALSE;
}
*
*****************************************************************************/
-ViewStmt: CREATE VIEW qualified_name opt_column_list AS SelectStmt
+ViewStmt: CREATE opt_or_replace VIEW qualified_name opt_column_list
+ AS SelectStmt
{
ViewStmt *n = makeNode(ViewStmt);
- n->view = $3;
- n->aliases = $4;
- n->query = (Query *) $6;
+ n->replace = $2;
+ n->view = $4;
+ n->aliases = $5;
+ n->query = (Query *) $7;
$$ = (Node *)n;
}
;
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteDefine.c,v 1.77 2002/08/05 03:29:17 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteDefine.c,v 1.78 2002/09/02 02:13:01 tgl Exp $
*
*-------------------------------------------------------------------------
*/
AttrNumber evslot_index,
bool evinstead,
Node *event_qual,
- List *action)
+ List *action,
+ bool replace)
{
char *evqual = nodeToString(event_qual);
char *actiontree = nodeToString((Node *) action);
int i;
Datum values[Natts_pg_rewrite];
char nulls[Natts_pg_rewrite];
+ char replaces[Natts_pg_rewrite];
NameData rname;
Relation pg_rewrite_desc;
- TupleDesc tupDesc;
- HeapTuple tup;
+ HeapTuple tup,
+ oldtup;
Oid rewriteObjectId;
ObjectAddress myself,
referenced;
-
- if (IsDefinedRewriteRule(eventrel_oid, rulname))
- elog(ERROR, "Attempt to insert rule \"%s\" failed: already exists",
- rulname);
+ bool is_update = false;
/*
* Set up *nulls and *values arrays
values[i++] = DirectFunctionCall1(textin, CStringGetDatum(actiontree)); /* ev_action */
/*
- * create a new pg_rewrite tuple
+ * Ready to store new pg_rewrite tuple
*/
pg_rewrite_desc = heap_openr(RewriteRelationName, RowExclusiveLock);
- tupDesc = pg_rewrite_desc->rd_att;
+ /*
+ * Check to see if we are replacing an existing tuple
+ */
+ oldtup = SearchSysCache(RULERELNAME,
+ ObjectIdGetDatum(eventrel_oid),
+ PointerGetDatum(rulname),
+ 0, 0);
+
+ if (HeapTupleIsValid(oldtup))
+ {
+ if (!replace)
+ elog(ERROR,"Attempt to insert rule \"%s\" failed: already exists",
+ rulname);
+
+ /*
+ * When replacing, we don't need to replace every attribute
+ */
+ MemSet(replaces, ' ', sizeof(replaces));
+ replaces[Anum_pg_rewrite_ev_attr - 1] = 'r';
+ replaces[Anum_pg_rewrite_ev_type - 1] = 'r';
+ replaces[Anum_pg_rewrite_is_instead - 1] = 'r';
+ replaces[Anum_pg_rewrite_ev_qual - 1] = 'r';
+ replaces[Anum_pg_rewrite_ev_action - 1] = 'r';
+
+ tup = heap_modifytuple(oldtup, pg_rewrite_desc,
+ values, nulls, replaces);
+
+ simple_heap_update(pg_rewrite_desc, &tup->t_self, tup);
- tup = heap_formtuple(tupDesc,
- values,
- nulls);
+ ReleaseSysCache(oldtup);
+
+ rewriteObjectId = HeapTupleGetOid(tup);
+ is_update = true;
+ }
+ else
+ {
+ tup = heap_formtuple(pg_rewrite_desc->rd_att, values, nulls);
- rewriteObjectId = simple_heap_insert(pg_rewrite_desc, tup);
+ rewriteObjectId = simple_heap_insert(pg_rewrite_desc, tup);
+ }
+ /* Need to update indexes in either case */
CatalogUpdateIndexes(pg_rewrite_desc, tup);
heap_freetuple(tup);
+ /* If replacing, get rid of old dependencies and make new ones */
+ if (is_update)
+ deleteDependencyRecordsFor(RelationGetRelid(pg_rewrite_desc),
+ rewriteObjectId);
+
/*
* Install dependency on rule's relation to ensure it will go away
* on relation deletion. If the rule is ON SELECT, make the dependency
referenced.objectSubId = 0;
recordDependencyOn(&myself, &referenced,
- (evtype == CMD_SELECT) ? DEPENDENCY_INTERNAL : DEPENDENCY_AUTO);
+ (evtype == CMD_SELECT) ? DEPENDENCY_INTERNAL : DEPENDENCY_AUTO);
/*
* Also install dependencies on objects referenced in action and qual.
*/
recordDependencyOnExpr(&myself, (Node *) action, NIL,
DEPENDENCY_NORMAL);
+
if (event_qual != NULL)
{
/* Find query containing OLD/NEW rtable entries */
Node *event_qual = stmt->whereClause;
CmdType event_type = stmt->event;
bool is_instead = stmt->instead;
+ bool replace = stmt->replace;
List *action = stmt->actions;
Relation event_relation;
Oid ev_relid;
* event relation, ...
*/
i = 0;
- foreach(tllist, query->targetList)
+ foreach (tllist, query->targetList)
{
TargetEntry *tle = (TargetEntry *) lfirst(tllist);
Resdom *resdom = tle->resdom;
/*
* ... there must not be another ON SELECT rule already ...
*/
- if (event_relation->rd_rules != NULL)
+ if (!replace && event_relation->rd_rules != NULL)
{
for (i = 0; i < event_relation->rd_rules->numLocks; i++)
{
event_attno,
is_instead,
event_qual,
- action);
+ action,
+ replace);
/*
* Set pg_class 'relhasrules' field TRUE for event relation. If
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.175 2002/08/30 19:23:20 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.176 2002/09/02 02:13:01 tgl Exp $
*
*-------------------------------------------------------------------------
*/
{
ViewStmt *stmt = (ViewStmt *) parsetree;
- DefineView(stmt->view, stmt->query);
+ DefineView(stmt->view, stmt->query, stmt->replace);
}
break;
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $Id: view.h,v 1.16 2002/07/01 15:27:56 tgl Exp $
+ * $Id: view.h,v 1.17 2002/09/02 02:13:02 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "nodes/parsenodes.h"
-extern void DefineView(const RangeVar *view, Query *view_parse);
+extern void DefineView(const RangeVar *view, Query *view_parse, bool replace);
extern void RemoveView(const RangeVar *view, DropBehavior behavior);
#endif /* VIEW_H */
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $Id: parsenodes.h,v 1.204 2002/08/31 22:10:47 tgl Exp $
+ * $Id: parsenodes.h,v 1.205 2002/09/02 02:13:02 tgl Exp $
*
*-------------------------------------------------------------------------
*/
CmdType event; /* SELECT, INSERT, etc */
bool instead; /* is a 'do instead'? */
List *actions; /* the action statements */
+ bool replace; /* OR REPLACE */
} RuleStmt;
/* ----------------------
RangeVar *view; /* the view to be created */
List *aliases; /* target column names */
Query *query; /* the SQL statement */
+ bool replace; /* replace an existing view? */
} ViewStmt;
/* ----------------------
CREATE VIEW toyemp AS
SELECT name, age, location, 12*salary AS annualsal
FROM emp;
+--
+-- CREATE OR REPLACE VIEW
+--
+CREATE TABLE viewtest_tbl (a int, b int);
+COPY viewtest_tbl FROM stdin;
+CREATE OR REPLACE VIEW viewtest AS
+ SELECT * FROM viewtest_tbl;
+CREATE OR REPLACE VIEW viewtest AS
+ SELECT * FROM viewtest_tbl WHERE a > 10;
+SELECT * FROM viewtest;
+ a | b
+----+----
+ 15 | 20
+ 20 | 25
+(2 rows)
+
+CREATE OR REPLACE VIEW viewtest AS
+ SELECT a, b FROM viewtest_tbl WHERE a > 5 ORDER BY b DESC;
+SELECT * FROM viewtest;
+ a | b
+----+----
+ 20 | 25
+ 15 | 20
+ 10 | 15
+(3 rows)
+
+-- should fail
+CREATE OR REPLACE VIEW viewtest AS
+ SELECT a FROM viewtest_tbl WHERE a <> 20;
+ERROR: Cannot change column set of existing view viewtest
+-- should fail
+CREATE OR REPLACE VIEW viewtest AS
+ SELECT 1, * FROM viewtest_tbl;
+ERROR: Cannot change column set of existing view viewtest
+-- should fail
+CREATE OR REPLACE VIEW viewtest AS
+ SELECT a, b::numeric FROM viewtest_tbl;
+ERROR: Cannot change column set of existing view viewtest
+DROP VIEW viewtest;
+DROP TABLE viewtest_tbl;
shoelace_ok | shoelace_ok_ins | CREATE RULE shoelace_ok_ins AS ON INSERT TO shoelace_ok DO INSTEAD UPDATE shoelace SET sl_avail = (shoelace.sl_avail + new.ok_quant) WHERE (shoelace.sl_name = new.ok_name);
(29 rows)
+--
+-- CREATE OR REPLACE RULE
+--
+CREATE TABLE ruletest_tbl (a int, b int);
+CREATE TABLE ruletest_tbl2 (a int, b int);
+CREATE OR REPLACE RULE myrule AS ON INSERT TO ruletest_tbl
+ DO INSTEAD INSERT INTO ruletest_tbl2 VALUES (10, 10);
+INSERT INTO ruletest_tbl VALUES (99, 99);
+CREATE OR REPLACE RULE myrule AS ON INSERT TO ruletest_tbl
+ DO INSTEAD INSERT INTO ruletest_tbl2 VALUES (1000, 1000);
+INSERT INTO ruletest_tbl VALUES (99, 99);
+SELECT * FROM ruletest_tbl2;
+ a | b
+------+------
+ 10 | 10
+ 1000 | 1000
+(2 rows)
+
SELECT name, age, location, 12*salary AS annualsal
FROM emp;
+--
+-- CREATE OR REPLACE VIEW
+--
+
+CREATE TABLE viewtest_tbl (a int, b int);
+COPY viewtest_tbl FROM stdin;
+5 10
+10 15
+15 20
+20 25
+\.
+
+CREATE OR REPLACE VIEW viewtest AS
+ SELECT * FROM viewtest_tbl;
+
+CREATE OR REPLACE VIEW viewtest AS
+ SELECT * FROM viewtest_tbl WHERE a > 10;
+
+SELECT * FROM viewtest;
+
+CREATE OR REPLACE VIEW viewtest AS
+ SELECT a, b FROM viewtest_tbl WHERE a > 5 ORDER BY b DESC;
+
+SELECT * FROM viewtest;
+
+-- should fail
+CREATE OR REPLACE VIEW viewtest AS
+ SELECT a FROM viewtest_tbl WHERE a <> 20;
+
+-- should fail
+CREATE OR REPLACE VIEW viewtest AS
+ SELECT 1, * FROM viewtest_tbl;
+
+-- should fail
+CREATE OR REPLACE VIEW viewtest AS
+ SELECT a, b::numeric FROM viewtest_tbl;
+
+DROP VIEW viewtest;
+DROP TABLE viewtest_tbl;
SELECT tablename, rulename, definition FROM pg_rules
ORDER BY tablename, rulename;
+--
+-- CREATE OR REPLACE RULE
+--
+
+CREATE TABLE ruletest_tbl (a int, b int);
+CREATE TABLE ruletest_tbl2 (a int, b int);
+
+CREATE OR REPLACE RULE myrule AS ON INSERT TO ruletest_tbl
+ DO INSTEAD INSERT INTO ruletest_tbl2 VALUES (10, 10);
+
+INSERT INTO ruletest_tbl VALUES (99, 99);
+
+CREATE OR REPLACE RULE myrule AS ON INSERT TO ruletest_tbl
+ DO INSTEAD INSERT INTO ruletest_tbl2 VALUES (1000, 1000);
+
+INSERT INTO ruletest_tbl VALUES (99, 99);
+
+SELECT * FROM ruletest_tbl2;
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