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Add CREATE OR REPLACE FUNCTION syntax to allow replacing a function

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definition without changing the function's OID, thereby not breaking
rules, views, triggers, etc that depend on it.  From Gavin Sherry.
This commit is contained in:
Tom Lane
2001-10-02 21:39:36 +00:00
parent f24fe14162
commit f2c657375d
12 changed files with 130 additions and 68 deletions
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36
doc/src/sgml/ref/create_function.sgml
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@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_function.sgml,v 1.26 2001/09/03 12:57:49 petere Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_function.sgml,v 1.27 2001/10/02 21:39:35 tgl Exp $
-->
<refentry id="SQL-CREATEFUNCTION">
@ -15,12 +15,12 @@ $Header: /cvsroot/pgsql/doc/src/sgml/ref/create_function.sgml,v 1.26 2001/09/03
<refsynopsisdiv>
<synopsis>
CREATE FUNCTION <replaceable class="parameter">name</replaceable> ( [ <replaceable class="parameter">argtype</replaceable> [, ...] ] )
CREATE [ OR REPLACE ] FUNCTION <replaceable class="parameter">name</replaceable> ( [ <replaceable class="parameter">argtype</replaceable> [, ...] ] )
RETURNS <replaceable class="parameter">rettype</replaceable>
AS '<replaceable class="parameter">definition</replaceable>'
LANGUAGE <replaceable class="parameter">langname</replaceable>
[ WITH ( <replaceable class="parameter">attribute</replaceable> [, ...] ) ]
CREATE FUNCTION <replaceable class="parameter">name</replaceable> ( [ <replaceable class="parameter">argtype</replaceable> [, ...] ] )
CREATE [ OR REPLACE ] FUNCTION <replaceable class="parameter">name</replaceable> ( [ <replaceable class="parameter">argtype</replaceable> [, ...] ] )
RETURNS <replaceable class="parameter">rettype</replaceable>
AS '<replaceable class="parameter">obj_file</replaceable>', '<replaceable class="parameter">link_symbol</replaceable>'
LANGUAGE <replaceable class="parameter">langname</replaceable>
@ -33,6 +33,8 @@ CREATE FUNCTION <replaceable class="parameter">name</replaceable> ( [ <replaceab
<para>
<command>CREATE FUNCTION</command> defines a new function.
<command>CREATE OR REPLACE FUNCTION</command> will either create
a new function, or replace an existing definition.
<variablelist>
<title>Parameters</title>
@ -202,11 +204,6 @@ CREATE FUNCTION <replaceable class="parameter">name</replaceable> ( [ <replaceab
for further information on writing external functions.
</para>
<para>
Use <command>DROP FUNCTION</command>
to remove user-defined functions.
</para>
<para>
The full <acronym>SQL</acronym> type syntax is allowed for
input arguments and return value. However, some details of the
@ -250,6 +247,29 @@ CREATE FUNCTION <replaceable class="parameter">name</replaceable> ( [ <replaceab
linkend="sql-load"> command.
</para>
<para>
Use <command>DROP FUNCTION</command>
to remove user-defined functions.
</para>
<para>
To update the definition of an existing function, use
<command>CREATE OR REPLACE FUNCTION</command>. Note that it is
not possible to change the name or argument types of a function
this way (if you tried, you'd just be creating a new, distinct
function). Also, <command>CREATE OR REPLACE FUNCTION</command>
will not let you change the return type of an existing function.
To do that, you must drop and re-create the function.
</para>
<para>
If you drop and then re-create a function, the new function is not
the same entity as the old; you will break existing rules, views,
triggers, etc that referred to the old function. Use
<command>CREATE OR REPLACE FUNCTION</command> to change a function
definition without breaking objects that refer to the function.
</para>
</refsect1>