@ -6,43 +6,43 @@
* 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 ;
@ -52,7 +52,7 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist)
* 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 ;
@ -83,23 +83,74 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist)
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 ;
@ -114,12 +165,13 @@ FormViewRetrieveRule(const RangeVar *view, Query *viewParse)
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 ;
@ -129,10 +181,9 @@ DefineViewRules(const RangeVar *view, Query *viewParse)
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 ) ;
@ -221,16 +272,18 @@ UpdateRangeTableOfViewParse(Oid viewOid, Query *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
@ -248,7 +301,7 @@ DefineView(const RangeVar *view, Query *viewParse)
/*
* Now create the rules associated with the view .
*/
DefineViewRules ( view , viewParse ) ;
DefineViewRules ( view , viewParse , replace ) ;
}
/*
Tom Lane
23 years ago