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This patch implements a different "relkind"
for views. Views are now have a "relkind" of RELKIND_VIEW instead of RELKIND_RELATION. Also, views no longer have actual heap storage files. The following changes were made 1. CREATE VIEW sets the new relkind 2. The executor complains if a DELETE or INSERT references a view. 3. DROP RULE complains if an attempt is made to delete a view SELECT rule. 4. CREATE RULE "_RETmytable" AS ON SELECT TO mytable DO INSTEAD ... 1. checks to make sure mytable is empty. 2. sets the relkind to RELKIND_VIEW. 3. deletes the heap storage files. 5. LOCK myview is not allowed. :) 6. the regression test type_sanity was changed to account for the new relkind value. 7. CREATE INDEX ON myview ... is not allowed. 8. VACUUM myview is not allowed. VACUUM automatically skips views when do the entire database. 9. TRUNCATE myview is not allowed. THINGS LEFT TO THINK ABOUT o pg_views o pg_dump o pgsql (\d \dv) o Do we really want to be able to inherit from views? o Is 'DROP TABLE myview' OK? -- Mark Hollomon
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-37
lines changed

14 files changed

+139
-37
lines changed

‎src/backend/catalog/heap.c

Lines changed: 5 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.142 2000/08/03 19:19:08 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.143 2000/09/12 04:49:06 momjian Exp $
1212
*
1313
*
1414
* INTERFACE ROUTINES
@@ -842,7 +842,9 @@ heap_create_with_catalog(char *relname,
842842
/*
843843
* We create the disk file for this relation here
844844
*/
845-
heap_storage_create(new_rel_desc);
845+
if (relkind != RELKIND_VIEW)
846+
heap_storage_create(new_rel_desc);
847+
846848
/* ----------------
847849
* ok, the relation has been cataloged, so close our relations
848850
* and return the oid of the newly created relation.
@@ -1468,7 +1470,7 @@ heap_drop_with_catalog(const char *relname,
14681470
* unlink the relation's physical file and finish up.
14691471
* ----------------
14701472
*/
1471-
if (! rel->rd_unlinked)
1473+
if (rel->rd_rel->relkind != RELKIND_VIEW && ! rel->rd_unlinked)
14721474
smgrunlink(DEFAULT_SMGR, rel);
14731475
rel->rd_unlinked = true;
14741476

‎src/backend/commands/command.c

Lines changed: 22 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/commands/Attic/command.c,v 1.100 2000/09/12 04:33:18 momjian Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/commands/Attic/command.c,v 1.101 2000/09/12 04:49:06 momjian Exp $
1212
*
1313
* NOTES
1414
* The PerformAddAttribute() code, like most of the relation
@@ -533,6 +533,9 @@ AlterTableAlterColumn(const char *relationName,
533533
#endif
534534

535535
rel = heap_openr(relationName, AccessExclusiveLock);
536+
if ( rel->rd_rel->relkind == RELKIND_VIEW )
537+
elog(ERROR, "ALTER TABLE: %s is a view", relationName);
538+
536539
myrelid = RelationGetRelid(rel);
537540
heap_close(rel, NoLock);
538541

@@ -1133,6 +1136,10 @@ AlterTableAddConstraint(char *relationName,
11331136

11341137
rel = heap_openr(relationName, AccessExclusiveLock);
11351138

1139+
/* make sure it is not a view */
1140+
if (rel->rd_rel->relkind == RELKIND_VIEW)
1141+
elog(ERROR, "ALTER TABLE: cannot add constraint to a view");
1142+
11361143
/*
11371144
* Scan all of the rows, looking for a false match
11381145
*/
@@ -1251,19 +1258,20 @@ AlterTableAddConstraint(char *relationName,
12511258
elog(ERROR, "ALTER TABLE / ADD CONSTRAINT: Unable to reference temporary table from permanent table constraint.");
12521259
}
12531260

1254-
/* check to see if the referenced table is a view. */
1255-
if (is_viewr(fkconstraint->pktable_name))
1256-
elog(ERROR, "ALTER TABLE: Cannot add constraints to views.");
1257-
12581261
/*
12591262
* Grab an exclusive lock on the pk table, so that someone
12601263
* doesn't delete rows out from under us.
12611264
*/
12621265

12631266
pkrel = heap_openr(fkconstraint->pktable_name, AccessExclusiveLock);
1264-
if (pkrel == NULL)
1265-
elog(ERROR, "referenced table \"%s\" not found",
1267+
if (pkrel == NULL)
1268+
elog(ERROR, "referenced table \"%s\" not found",
1269+
fkconstraint->pktable_name);
1270+
1271+
if (pkrel->rd_rel->relkind != RELKIND_RELATION)
1272+
elog(ERROR, "referenced table \"%s\" not a relation",
12661273
fkconstraint->pktable_name);
1274+
12671275

12681276
/*
12691277
* Grab an exclusive lock on the fk table, and then scan
@@ -1277,6 +1285,9 @@ AlterTableAddConstraint(char *relationName,
12771285
elog(ERROR, "table \"%s\" not found",
12781286
relationName);
12791287

1288+
if (rel->rd_rel->relkind != RELKIND_RELATION)
1289+
elog(ERROR, "referencing table \"%s\" not a relation", relationName);
1290+
12801291
/* First we check for limited correctness of the constraint */
12811292

12821293
rel_attrs = pkrel->rd_att->attrs;
@@ -1503,6 +1514,7 @@ AlterTableCreateToastTable(const char *relationName, bool silent)
15031514
* allow to create TOAST tables for views. But why not - someone
15041515
* can insert into a view, so it shouldn't be impossible to hide
15051516
* huge data there :-)
1517+
* Not any more.
15061518
*/
15071519
if (((Form_pg_class) GETSTRUCT(reltup))->relkind != RELKIND_RELATION)
15081520
{
@@ -1702,6 +1714,9 @@ LockTableCommand(LockStmt *lockstmt)
17021714

17031715
rel = heap_openr(lockstmt->relname, NoLock);
17041716

1717+
if (rel->rd_rel->relkind != RELKIND_RELATION)
1718+
elog(ERROR, "LOCK TABLE: %s is not a table", lockstmt->relname);
1719+
17051720
if (is_view(rel))
17061721
elog(ERROR, "LOCK TABLE: cannot lock a view");
17071722

‎src/backend/commands/comment.c

Lines changed: 5 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -21,6 +21,7 @@
2121
#include "catalog/pg_shadow.h"
2222
#include "catalog/pg_trigger.h"
2323
#include "catalog/pg_type.h"
24+
#include "catalog/pg_class.h"
2425
#include "commands/comment.h"
2526
#include "miscadmin.h"
2627
#include "parser/parse.h"
@@ -301,19 +302,19 @@ CommentRelation(int reltype, char *relname, char *comment)
301302
switch (reltype)
302303
{
303304
case (INDEX):
304-
if (relkind != 'i')
305+
if (relkind != RELKIND_INDEX)
305306
elog(ERROR, "relation '%s' is not an index", relname);
306307
break;
307308
case (TABLE):
308-
if (relkind != 'r')
309+
if (relkind != RELKIND_RELATION)
309310
elog(ERROR, "relation '%s' is not a table", relname);
310311
break;
311312
case (VIEW):
312-
if (relkind != 'r')
313+
if (relkind != RELKIND_VIEW)
313314
elog(ERROR, "relation '%s' is not a view", relname);
314315
break;
315316
case (SEQUENCE):
316-
if (relkind != 'S')
317+
if (relkind != RELKIND_SEQUENCE)
317318
elog(ERROR, "relation '%s' is not a sequence", relname);
318319
break;
319320
}

‎src/backend/commands/vacuum.c

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.164 2000/09/06 14:15:16 petere Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.165 2000/09/12 04:49:07 momjian Exp $
1212
*
1313
1414
*-------------------------------------------------------------------------
@@ -306,7 +306,7 @@ getrels(NameData *VacRelP)
306306

307307
if (rkind != RELKIND_RELATION)
308308
{
309-
elog(NOTICE, "Vacuum: can not process index and certain system tables");
309+
elog(NOTICE, "Vacuum: can not process indecies, views and certain system tables");
310310
continue;
311311
}
312312

‎src/backend/commands/view.c

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -6,7 +6,7 @@
66
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
77
* Portions Copyright (c) 1994, Regents of the University of California
88
*
9-
* $Id: view.c,v 1.46 2000/09/12 04:15:56 momjian Exp $
9+
* $Id: view.c,v 1.47 2000/09/12 04:49:07 momjian Exp $
1010
*
1111
*-------------------------------------------------------------------------
1212
*/
@@ -102,7 +102,7 @@ DefineVirtualRelation(char *relname, List *tlist)
102102
/*
103103
* finally create the relation...
104104
*/
105-
DefineRelation(&createStmt, RELKIND_RELATION);
105+
DefineRelation(&createStmt, RELKIND_VIEW);
106106
}
107107

108108
/*------------------------------------------------------------------

‎src/backend/executor/execMain.c

Lines changed: 5 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -27,7 +27,7 @@
2727
*
2828
*
2929
* IDENTIFICATION
30-
* $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.125 2000/09/06 14:15:17 petere Exp $
30+
* $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.126 2000/09/12 04:49:08 momjian Exp $
3131
*
3232
*-------------------------------------------------------------------------
3333
*/
@@ -720,6 +720,10 @@ InitPlan(CmdType operation, Query *parseTree, Plan *plan, EState *estate)
720720
elog(ERROR, "You can't change toast relation %s",
721721
RelationGetRelationName(resultRelationDesc));
722722

723+
if (resultRelationDesc->rd_rel->relkind == RELKIND_VIEW)
724+
elog(ERROR, "You can't change view relation %s",
725+
RelationGetRelationName(resultRelationDesc));
726+
723727
resultRelationInfo = makeNode(RelationInfo);
724728
resultRelationInfo->ri_RangeTableIndex = resultRelationIndex;
725729
resultRelationInfo->ri_RelationDesc = resultRelationDesc;

‎src/backend/rewrite/rewriteDefine.c

Lines changed: 69 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteDefine.c,v 1.50 2000/09/12 04:15:57 momjian Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteDefine.c,v 1.51 2000/09/12 04:49:09 momjian Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -23,6 +23,8 @@
2323
#include "parser/parse_relation.h"
2424
#include "rewrite/rewriteDefine.h"
2525
#include "rewrite/rewriteSupport.h"
26+
#include "utils/syscache.h"
27+
#include "storage/smgr.h"
2628
#include "commands/view.h"
2729

2830

@@ -162,6 +164,7 @@ DefineQueryRewrite(RuleStmt *stmt)
162164
*event_qualP;
163165
List *l;
164166
Query *query;
167+
bool RelisBecomingView = false;
165168

166169
/*
167170
* If we are installing an ON SELECT rule, we had better grab
@@ -207,6 +210,30 @@ DefineQueryRewrite(RuleStmt *stmt)
207210
elog(ERROR, "rule actions on NEW currently not supported"
208211
"\n\tuse triggers instead");
209212
}
213+
214+
if (event_relation->rd_rel->relkind != RELKIND_VIEW)
215+
{
216+
HeapScanDesc scanDesc;
217+
HeapTuple tuple;
218+
/*
219+
* A relation is about to become a view.
220+
* check that the relation is empty because
221+
* the storage for the relation is going to
222+
* be deleted.
223+
*/
224+
225+
scanDesc = heap_beginscan(event_relation, 0, SnapshotNow, 0, NULL);
226+
tuple = heap_getnext(scanDesc, 0);
227+
if (HeapTupleIsValid(tuple))
228+
elog(ERROR, "relation %s is not empty. Cannot convert to view", event_obj->relname);
229+
230+
/* don't need heap_freetuple because we never got a valid tuple */
231+
heap_endscan(scanDesc);
232+
233+
234+
RelisBecomingView = true;
235+
}
236+
210237
}
211238

212239
/*
@@ -338,6 +365,10 @@ DefineQueryRewrite(RuleStmt *stmt)
338365
/* discard rule if it's null action and not INSTEAD; it's a no-op */
339366
if (action != NULL || is_instead)
340367
{
368+
Relation relationRelation;
369+
HeapTuple tuple;
370+
Relation idescs[Num_pg_class_indices];
371+
341372
event_qualP = nodeToString(event_qual);
342373
actionP = nodeToString(action);
343374

@@ -351,14 +382,50 @@ DefineQueryRewrite(RuleStmt *stmt)
351382

352383
/*
353384
* Set pg_class 'relhasrules' field TRUE for event relation.
385+
* Also modify the 'relkind' field to show that the relation is
386+
* now a view.
354387
*
355388
* Important side effect: an SI notice is broadcast to force all
356389
* backends (including me!) to update relcache entries with the new
357390
* rule.
391+
*
392+
* NOTE : Used to call setRelhasrulesInRelation. The code
393+
* was inlined so that two updates were not needed. mhh 31-aug-2000
394+
*/
395+
396+
/*
397+
* Find the tuple to update in pg_class, using syscache for the lookup.
358398
*/
359-
setRelhasrulesInRelation(ev_relid, true);
399+
relationRelation = heap_openr(RelationRelationName, RowExclusiveLock);
400+
tuple = SearchSysCacheTupleCopy(RELOID,
401+
ObjectIdGetDatum(ev_relid),
402+
0, 0, 0);
403+
Assert(HeapTupleIsValid(tuple));
404+
405+
/* Do the update */
406+
((Form_pg_class) GETSTRUCT(tuple))->relhasrules = true;
407+
if (RelisBecomingView)
408+
((Form_pg_class) GETSTRUCT(tuple))->relkind = RELKIND_VIEW;
409+
410+
heap_update(relationRelation, &tuple->t_self, tuple, NULL);
411+
412+
/* Keep the catalog indices up to date */
413+
CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, idescs);
414+
CatalogIndexInsert(idescs, Num_pg_class_indices, relationRelation, tuple);
415+
CatalogCloseIndices(Num_pg_class_indices, idescs);
416+
417+
heap_freetuple(tuple);
418+
heap_close(relationRelation, RowExclusiveLock);
360419
}
361420

421+
/*
422+
* IF the relation is becoming a view, delete the storage
423+
* files associated with it.
424+
*/
425+
if (RelisBecomingView)
426+
smgrunlink(DEFAULT_SMGR, event_relation);
427+
428+
362429
/* Close rel, but keep lock till commit... */
363430
heap_close(event_relation, NoLock);
364431
}

‎src/backend/rewrite/rewriteRemove.c

Lines changed: 6 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteRemove.c,v 1.38 2000/06/30 07:04:23 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteRemove.c,v 1.39 2000/09/12 04:49:09 momjian Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -103,6 +103,11 @@ RemoveRewriteRule(char *ruleName)
103103
*/
104104
event_relation = heap_open(eventRelationOid, AccessExclusiveLock);
105105

106+
/* do not allow the removal of a view's SELECT rule */
107+
if (event_relation->rd_rel->relkind == RELKIND_VIEW &&
108+
((Form_pg_rewrite) GETSTRUCT(tuple))->ev_type == '1' )
109+
elog(ERROR, "Cannot remove a view's SELECT rule");
110+
106111
hasMoreRules = event_relation->rd_rules != NULL &&
107112
event_relation->rd_rules->numLocks > 1;
108113

‎src/backend/tcop/utility.c

Lines changed: 4 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,7 @@
1010
*
1111
*
1212
* IDENTIFICATION
13-
* $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.92 2000/09/06 14:15:21 petere Exp $
13+
* $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.93 2000/09/12 04:49:11 momjian Exp $
1414
*
1515
*-------------------------------------------------------------------------
1616
*/
@@ -228,6 +228,9 @@ ProcessUtility(Node *parsetree,
228228
if (rel->rd_rel->relkind == RELKIND_SEQUENCE)
229229
elog(ERROR, "TRUNCATE cannot be used on sequences. '%s' is a sequence",
230230
relname);
231+
if (rel->rd_rel->relkind == RELKIND_VIEW)
232+
elog(ERROR, "TRUNCATE cannot be used on views. '%s' is a sequence",
233+
relname);
231234
heap_close(rel, NoLock);
232235

233236
#ifndef NO_SECURITY

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