mirror of
https://git.postgresql.org/git/postgresql.git
synced 2025-01-30 19:00:29 +08:00
Department of second thoughts: make checks for replacing a view slightly
more flexible, and improve the error reporting. Also, add documentation for REPLACE RULE/VIEW.
This commit is contained in:
Tom Lane
parent
b4d24d78a9
commit
8f60f43f2e
@ -1,5 +1,5 @@
|
||||
<!--
|
||||
$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_rule.sgml,v 1.36 2002/05/18 15:44:47 petere Exp $
|
||||
$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_rule.sgml,v 1.37 2002/09/02 20:04:39 tgl Exp $
|
||||
PostgreSQL documentation
|
||||
-->
|
||||
|
||||
@ -21,17 +21,15 @@ PostgreSQL documentation
|
||||
<date>2001-01-05</date>
|
||||
</refsynopsisdivinfo>
|
||||
<synopsis>
|
||||
CREATE RULE <replaceable class="parameter">name</replaceable> AS ON <replaceable class="parameter">event</replaceable>
|
||||
CREATE [ OR REPLACE ] RULE <replaceable class="parameter">name</replaceable> AS ON <replaceable class="parameter">event</replaceable>
|
||||
TO <replaceable class="parameter">table</replaceable> [ WHERE <replaceable class="parameter">condition</replaceable> ]
|
||||
DO [ INSTEAD ] <replaceable class="parameter">action</replaceable>
|
||||
|
||||
where <replaceable class="PARAMETER">action</replaceable> can be:
|
||||
|
||||
NOTHING
|
||||
|
|
||||
<replaceable class="parameter">query</replaceable>
|
||||
|
|
||||
( <replaceable class="parameter">query</replaceable> ; <replaceable class="parameter">query</replaceable> ... )
|
||||
| <replaceable class="parameter">query</replaceable>
|
||||
| ( <replaceable class="parameter">query</replaceable> ; <replaceable class="parameter">query</replaceable> ... )
|
||||
</synopsis>
|
||||
|
||||
<refsect2 id="R2-SQL-CREATERULE-1">
|
||||
@ -76,9 +74,10 @@ NOTHING
|
||||
<term><replaceable class="parameter">condition</replaceable></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Any SQL conditional expression (returning <type>boolean</type>). The condition expression may not
|
||||
Any SQL conditional expression (returning <type>boolean</type>).
|
||||
The condition expression may not
|
||||
refer to any tables except <literal>new</literal> and
|
||||
<literal>old</literal>.
|
||||
<literal>old</literal>, and may not contain aggregate functions.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
@ -142,6 +141,14 @@ CREATE RULE
|
||||
Description
|
||||
</title>
|
||||
|
||||
<para>
|
||||
<command>CREATE RULE</command> defines a new rule applying to a specified
|
||||
table or view.
|
||||
<command>CREATE OR REPLACE RULE</command> will either create a
|
||||
new rule, or replace an existing rule of the same name for the same
|
||||
table.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
The <productname>PostgreSQL</productname>
|
||||
<firstterm>rule system</firstterm> allows one to define an
|
||||
@ -318,7 +325,7 @@ UPDATE mytable SET name = 'foo' WHERE id = 42;
|
||||
</title>
|
||||
|
||||
<para>
|
||||
<command>CREATE RULE</command> statement is a <productname>PostgreSQL</productname>
|
||||
<command>CREATE RULE</command> is a <productname>PostgreSQL</productname>
|
||||
language extension.
|
||||
There is no <command>CREATE RULE</command> statement in <acronym>SQL92</acronym>.
|
||||
</para>
|
||||
|
||||
@ -1,5 +1,5 @@
|
||||
<!--
|
||||
$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_view.sgml,v 1.18 2002/05/18 15:44:47 petere Exp $
|
||||
$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_view.sgml,v 1.19 2002/09/02 20:04:39 tgl Exp $
|
||||
PostgreSQL documentation
|
||||
-->
|
||||
|
||||
@ -21,7 +21,7 @@ PostgreSQL documentation
|
||||
<date>2000-03-25</date>
|
||||
</refsynopsisdivinfo>
|
||||
<synopsis>
|
||||
CREATE VIEW <replaceable class="PARAMETER">view</replaceable> [ ( <replaceable
|
||||
CREATE [ OR REPLACE ] VIEW <replaceable class="PARAMETER">view</replaceable> [ ( <replaceable
|
||||
class="PARAMETER">column name list</replaceable> ) ] AS SELECT <replaceable class="PARAMETER">query</replaceable>
|
||||
</synopsis>
|
||||
|
||||
@ -132,13 +132,21 @@ CREATE VIEW vista AS SELECT text 'Hello World'
|
||||
<title>
|
||||
Description
|
||||
</title>
|
||||
|
||||
<para>
|
||||
<command>CREATE VIEW</command> will define a view of a query.
|
||||
<command>CREATE VIEW</command> defines a view of a query.
|
||||
The view is not physically materialized. Instead, a query
|
||||
rewrite rule (an <literal>ON SELECT</> rule) is automatically generated to
|
||||
support SELECT operations on views.
|
||||
</para>
|
||||
|
||||
<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).
|
||||
</para>
|
||||
|
||||
<para>
|
||||
If a schema name is given (for example, <literal>CREATE VIEW
|
||||
myschema.myview ...</>) then the view is created in the
|
||||
@ -206,6 +214,7 @@ SELECT * FROM kinds;
|
||||
<title>
|
||||
SQL92
|
||||
</title>
|
||||
|
||||
<para>
|
||||
SQL92 specifies some additional capabilities for the
|
||||
<command>CREATE VIEW</command> statement:
|
||||
@ -253,6 +262,12 @@ CREATE VIEW <replaceable class="parameter">view</replaceable> [ <replaceable cla
|
||||
</varlistentry>
|
||||
</variablelist>
|
||||
</para>
|
||||
|
||||
<para>
|
||||
<command>CREATE OR REPLACE VIEW</command> is a
|
||||
<productname>PostgreSQL</productname> language extension.
|
||||
</para>
|
||||
|
||||
</refsect2>
|
||||
</refsect1>
|
||||
</refentry>
|
||||
|
||||
@ -1,5 +1,5 @@
|
||||
<!--
|
||||
$Header: /cvsroot/pgsql/doc/src/sgml/release.sgml,v 1.156 2002/08/30 22:18:05 tgl Exp $
|
||||
$Header: /cvsroot/pgsql/doc/src/sgml/release.sgml,v 1.157 2002/09/02 20:04:39 tgl Exp $
|
||||
-->
|
||||
|
||||
<appendix id="release">
|
||||
@ -24,6 +24,7 @@ CDATA means the content is "SGML-free", so you can write without
|
||||
worries about funny characters.
|
||||
-->
|
||||
<literallayout><![CDATA[
|
||||
CREATE OR REPLACE VIEW, CREATE OR REPLACE RULE are available
|
||||
No-autocommit mode is available (set autocommit to off)
|
||||
Substantial improvements in functionality for functions returning sets
|
||||
Client libraries older than 6.3 no longer supported (version 0 protocol removed)
|
||||
|
||||
@ -8,7 +8,7 @@
|
||||
*
|
||||
*
|
||||
* IDENTIFICATION
|
||||
* $Header: /cvsroot/pgsql/src/backend/commands/view.c,v 1.69 2002/09/02 02:13:01 tgl Exp $
|
||||
* $Header: /cvsroot/pgsql/src/backend/commands/view.c,v 1.70 2002/09/02 20:04:40 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
@ -29,6 +29,9 @@
|
||||
#include "utils/lsyscache.h"
|
||||
|
||||
|
||||
static void checkViewTupleDesc(TupleDesc newdesc, TupleDesc olddesc);
|
||||
|
||||
|
||||
/*---------------------------------------------------------------------
|
||||
* DefineVirtualRelation
|
||||
*
|
||||
@ -111,15 +114,9 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist, bool replace)
|
||||
/*
|
||||
* 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));
|
||||
checkViewTupleDesc(descriptor, rel->rd_att);
|
||||
|
||||
/*
|
||||
* Seems okay, so return the OID of the pre-existing view.
|
||||
@ -149,6 +146,46 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist, bool replace)
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* Verify that tupledesc associated with proposed new view definition
|
||||
* matches tupledesc of old view. This is basically a cut-down version
|
||||
* of equalTupleDescs(), with code added to generate specific complaints.
|
||||
*/
|
||||
static void
|
||||
checkViewTupleDesc(TupleDesc newdesc, TupleDesc olddesc)
|
||||
{
|
||||
int i;
|
||||
|
||||
if (newdesc->natts != olddesc->natts)
|
||||
elog(ERROR, "Cannot change number of columns in view");
|
||||
/* we can ignore tdhasoid */
|
||||
|
||||
for (i = 0; i < newdesc->natts; i++)
|
||||
{
|
||||
Form_pg_attribute newattr = newdesc->attrs[i];
|
||||
Form_pg_attribute oldattr = olddesc->attrs[i];
|
||||
|
||||
/* XXX not right, but we don't support DROP COL on view anyway */
|
||||
if (newattr->attisdropped != oldattr->attisdropped)
|
||||
elog(ERROR, "Cannot change number of columns in view");
|
||||
|
||||
if (strcmp(NameStr(newattr->attname), NameStr(oldattr->attname)) != 0)
|
||||
elog(ERROR, "Cannot change name of view column \"%s\"",
|
||||
NameStr(oldattr->attname));
|
||||
/* XXX would it be safe to allow atttypmod to change? Not sure */
|
||||
if (newattr->atttypid != oldattr->atttypid ||
|
||||
newattr->atttypmod != oldattr->atttypmod)
|
||||
elog(ERROR, "Cannot change datatype of view column \"%s\"",
|
||||
NameStr(oldattr->attname));
|
||||
/* We can ignore the remaining attributes of an attribute... */
|
||||
}
|
||||
/*
|
||||
* We ignore the constraint fields. The new view desc can't have any
|
||||
* constraints, and the only ones that could be on the old view are
|
||||
* defaults, which we are happy to leave in place.
|
||||
*/
|
||||
}
|
||||
|
||||
static RuleStmt *
|
||||
FormViewRetrieveRule(const RangeVar *view, Query *viewParse, bool replace)
|
||||
{
|
||||
|
||||
@ -44,14 +44,14 @@ SELECT * FROM viewtest;
|
||||
-- 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
|
||||
ERROR: Cannot change number of columns in view
|
||||
-- should fail
|
||||
CREATE OR REPLACE VIEW viewtest AS
|
||||
SELECT 1, * FROM viewtest_tbl;
|
||||
ERROR: Cannot change column set of existing view viewtest
|
||||
ERROR: Cannot change number of columns in view
|
||||
-- should fail
|
||||
CREATE OR REPLACE VIEW viewtest AS
|
||||
SELECT a, b::numeric FROM viewtest_tbl;
|
||||
ERROR: Cannot change column set of existing view viewtest
|
||||
ERROR: Cannot change datatype of view column "b"
|
||||
DROP VIEW viewtest;
|
||||
DROP TABLE viewtest_tbl;
|
||||
|
||||
Loading…
Reference in New Issue
Block a user