<!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/create_view.sgml,v 1.37 2008/11/14 10:22:46 petere Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/create_view.sgml,v 1.38 2008/12/06 23:22:46 momjian Exp $
PostgreSQL documentation
-->
<para>
<command>CREATE OR REPLACE VIEW</command> is similar, but if a view
- of the same name already exists, it is replaced. You can only replace
- a view with a new query that generates the identical set of columns
- (i.e., same column names and data types).
+ of the same name already exists, it is replaced. The new query must
+ generate all of the same columns that were generated by the original query
+ in the same order and with the same data types, but may add additional
+ columns to the end of the list.
</para>
<para>
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.271 2008/11/19 10:34:51 heikki Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.272 2008/12/06 23:22:46 momjian Exp $
*
*-------------------------------------------------------------------------
*/
ATPrepAddColumn(wqueue, rel, recurse, cmd);
pass = AT_PASS_ADD_COL;
break;
+ case AT_AddColumnToView: /* add column via CREATE OR REPLACE VIEW */
+ ATSimplePermissions(rel, true);
+ /* Performs own recursion */
+ ATPrepAddColumn(wqueue, rel, recurse, cmd);
+ pass = AT_PASS_ADD_COL;
+ break;
case AT_ColumnDefault: /* ALTER COLUMN DEFAULT */
/*
switch (cmd->subtype)
{
case AT_AddColumn: /* ADD COLUMN */
+ case AT_AddColumnToView: /* add column via CREATE OR REPLACE VIEW */
ATExecAddColumn(tab, rel, (ColumnDef *) cmd->def);
break;
case AT_ColumnDefault: /* ALTER COLUMN DEFAULT */
int i;
int minattnum,
maxatts;
+ char relkind;
HeapTuple typeTuple;
Oid typeOid;
int32 typmod;
colDef->colname, RelationGetRelationName(rel))));
minattnum = ((Form_pg_class) GETSTRUCT(reltup))->relnatts;
+ relkind = ((Form_pg_class) GETSTRUCT(reltup))->relkind;
maxatts = minattnum + 1;
if (maxatts > MaxHeapAttributeNumber)
ereport(ERROR,
* Note: we use build_column_default, and not just the cooked default
* returned by AddRelationNewConstraints, so that the right thing happens
* when a datatype's default applies.
+ *
+ * We skip this logic completely for views.
*/
- defval = (Expr *) build_column_default(rel, attribute.attnum);
+ if (relkind != RELKIND_VIEW) {
+ defval = (Expr *) build_column_default(rel, attribute.attnum);
- if (!defval && GetDomainConstraints(typeOid) != NIL)
- {
- Oid baseTypeId;
- int32 baseTypeMod;
-
- baseTypeMod = typmod;
- baseTypeId = getBaseTypeAndTypmod(typeOid, &baseTypeMod);
- defval = (Expr *) makeNullConst(baseTypeId, baseTypeMod);
- defval = (Expr *) coerce_to_target_type(NULL,
- (Node *) defval,
- baseTypeId,
- typeOid,
- typmod,
- COERCION_ASSIGNMENT,
- COERCE_IMPLICIT_CAST,
- -1);
- if (defval == NULL) /* should not happen */
- elog(ERROR, "failed to coerce base type to domain");
- }
+ if (!defval && GetDomainConstraints(typeOid) != NIL)
+ {
+ Oid baseTypeId;
+ int32 baseTypeMod;
+
+ baseTypeMod = typmod;
+ baseTypeId = getBaseTypeAndTypmod(typeOid, &baseTypeMod);
+ defval = (Expr *) makeNullConst(baseTypeId, baseTypeMod);
+ defval = (Expr *) coerce_to_target_type(NULL,
+ (Node *) defval,
+ baseTypeId,
+ typeOid,
+ typmod,
+ COERCION_ASSIGNMENT,
+ COERCE_IMPLICIT_CAST,
+ -1);
+ if (defval == NULL) /* should not happen */
+ elog(ERROR, "failed to coerce base type to domain");
+ }
- if (defval)
- {
- NewColumnValue *newval;
+ if (defval)
+ {
+ NewColumnValue *newval;
- newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
- newval->attnum = attribute.attnum;
- newval->expr = defval;
+ newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
+ newval->attnum = attribute.attnum;
+ newval->expr = defval;
- tab->newvals = lappend(tab->newvals, newval);
- }
+ tab->newvals = lappend(tab->newvals, newval);
+ }
- /*
- * If the new column is NOT NULL, tell Phase 3 it needs to test that.
- */
- tab->new_notnull |= colDef->is_not_null;
+ /*
+ * If the new column is NOT NULL, tell Phase 3 it needs to test that.
+ */
+ tab->new_notnull |= colDef->is_not_null;
+ }
/*
* Add needed dependency entries for the new column.
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/view.c,v 1.107 2008/08/25 22:42:32 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/view.c,v 1.108 2008/12/06 23:22:46 momjian Exp $
*
*-------------------------------------------------------------------------
*/
*/
Assert(relation->istemp == rel->rd_istemp);
+ /*
+ * If new attributes have been added, we must modify the pre-existing
+ * view.
+ */
+ if (list_length(attrList) > rel->rd_att->natts) {
+ List *atcmds = NIL;
+ ListCell *c;
+ int skip = rel->rd_att->natts;
+
+ foreach(c, attrList) {
+ AlterTableCmd *atcmd;
+
+ if (skip > 0) {
+ --skip;
+ continue;
+ }
+ atcmd = makeNode(AlterTableCmd);
+ atcmd->subtype = AT_AddColumnToView;
+ atcmd->def = lfirst(c);
+ atcmds = lappend(atcmds, atcmd);
+ }
+ AlterTableInternal(viewOid, atcmds, true);
+ }
+
/*
* Create a tuple descriptor to compare against the existing view, and
- * verify it matches.
+ * verify that the old column list is an initial prefix of the new
+ * column list.
*/
descriptor = BuildDescForRelation(attrList);
checkViewTupleDesc(descriptor, rel->rd_att);
{
int i;
- if (newdesc->natts != olddesc->natts)
+ if (newdesc->natts < olddesc->natts)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
- errmsg("cannot change number of columns in view")));
+ errmsg("cannot drop columns from view")));
/* we can ignore tdhasoid */
- for (i = 0; i < newdesc->natts; i++)
+ for (i = 0; i < olddesc->natts; i++)
{
Form_pg_attribute newattr = newdesc->attrs[i];
Form_pg_attribute oldattr = olddesc->attrs[i];
if (newattr->attisdropped != oldattr->attisdropped)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
- errmsg("cannot change number of columns in view")));
+ errmsg("cannot drop columns from view")));
if (strcmp(NameStr(newattr->attname), NameStr(oldattr->attname)) != 0)
ereport(ERROR,
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/backend/parser/parse_utilcmd.c,v 2.17 2008/09/01 20:42:45 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/parser/parse_utilcmd.c,v 2.18 2008/12/06 23:22:46 momjian Exp $
*
*-------------------------------------------------------------------------
*/
switch (cmd->subtype)
{
case AT_AddColumn:
+ case AT_AddColumnToView:
{
ColumnDef *def = (ColumnDef *) cmd->def;
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.381 2008/12/04 17:51:27 petere Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.382 2008/12/06 23:22:46 momjian Exp $
*
*-------------------------------------------------------------------------
*/
typedef enum AlterTableType
{
AT_AddColumn, /* add column */
+ AT_AddColumnToView, /* implicitly via CREATE OR REPLACE VIEW */
AT_ColumnDefault, /* alter column default */
AT_DropNotNull, /* alter column drop not null */
AT_SetNotNull, /* alter column set not null */
-- should fail
CREATE OR REPLACE VIEW viewtest AS
SELECT a FROM viewtest_tbl WHERE a <> 20;
-ERROR: cannot change number of columns in view
+ERROR: cannot drop columns from view
-- should fail
CREATE OR REPLACE VIEW viewtest AS
SELECT 1, * FROM viewtest_tbl;
-ERROR: cannot change number of columns in view
+ERROR: column "b" of relation "viewtest" already exists
-- should fail
CREATE OR REPLACE VIEW viewtest AS
SELECT a, b::numeric FROM viewtest_tbl;
ERROR: cannot change data type of view column "b"
+-- should work
+CREATE OR REPLACE VIEW viewtest AS
+ SELECT a, b, 0 AS c FROM viewtest_tbl;
DROP VIEW viewtest;
DROP TABLE viewtest_tbl;
-- tests for temporary views
CREATE OR REPLACE VIEW viewtest AS
SELECT a, b::numeric FROM viewtest_tbl;
+-- should work
+CREATE OR REPLACE VIEW viewtest AS
+ SELECT a, b, 0 AS c FROM viewtest_tbl;
+
DROP VIEW viewtest;
DROP TABLE viewtest_tbl;
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