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-rw-r--r--doc/src/sgml/func.sgml20
-rw-r--r--doc/src/sgml/ref/create_function.sgml26
-rw-r--r--doc/src/sgml/xfunc.sgml56
3 files changed, 96 insertions, 6 deletions
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 67500340b0f..23241c24697 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.460 2008/11/14 00:51:46 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.461 2008/12/04 17:51:26 petere Exp $ -->
<chapter id="functions">
<title>Functions and Operators</title>
@@ -11711,6 +11711,10 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
</indexterm>
<indexterm>
+ <primary>pg_get_function_identity_arguments</primary>
+ </indexterm>
+
+ <indexterm>
<primary>pg_get_function_result</primary>
</indexterm>
@@ -11799,7 +11803,12 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
<row>
<entry><literal><function>pg_get_function_arguments</function>(<parameter>func_oid</parameter>)</literal></entry>
<entry><type>text</type></entry>
- <entry>get argument list for function</entry>
+ <entry>get argument list of function's definition (with default values)</entry>
+ </row>
+ <row>
+ <entry><literal><function>pg_get_function_identity_arguments</function>(<parameter>func_oid</parameter>)</literal></entry>
+ <entry><type>text</type></entry>
+ <entry>get argument list to identify a function (without argument names, default values)</entry>
</row>
<row>
<entry><literal><function>pg_get_function_result</function>(<parameter>func_oid</parameter>)</literal></entry>
@@ -11920,7 +11929,12 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
of a function, in the form it would need to appear in within
<command>CREATE FUNCTION</>.
<function>pg_get_function_result</function> similarly returns the
- appropriate <literal>RETURNS</> clause for the function.
+ appropriate <literal>RETURNS</> clause for the function.
+ <function>pg_get_function_identity_arguments</function> returns the
+ argument list necessary to identify a function, in the form it
+ would need to appear in within <command>ALTER FUNCTION</>, for
+ instance. This form omits default values and argument names, for
+ example.
</para>
<para>
diff --git a/doc/src/sgml/ref/create_function.sgml b/doc/src/sgml/ref/create_function.sgml
index a6af57a22bf..5de4967789d 100644
--- a/doc/src/sgml/ref/create_function.sgml
+++ b/doc/src/sgml/ref/create_function.sgml
@@ -1,5 +1,5 @@
<!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/create_function.sgml,v 1.81 2008/11/14 10:22:46 petere Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/create_function.sgml,v 1.82 2008/12/04 17:51:26 petere Exp $
-->
<refentry id="SQL-CREATEFUNCTION">
@@ -21,7 +21,7 @@ $PostgreSQL: pgsql/doc/src/sgml/ref/create_function.sgml,v 1.81 2008/11/14 10:22
<refsynopsisdiv>
<synopsis>
CREATE [ OR REPLACE ] FUNCTION
- <replaceable class="parameter">name</replaceable> ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] )
+ <replaceable class="parameter">name</replaceable> ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [ { DEFAULT | = } <replaceable class="parameter">defexpr</replaceable>] [, ...] ] )
[ RETURNS <replaceable class="parameter">rettype</replaceable>
| RETURNS TABLE ( <replaceable class="parameter">colname</replaceable> <replaceable class="parameter">coltype</replaceable> [, ...] ) ]
{ LANGUAGE <replaceable class="parameter">langname</replaceable>
@@ -155,6 +155,20 @@ CREATE [ OR REPLACE ] FUNCTION
</varlistentry>
<varlistentry>
+ <term><replaceable class="parameter">defexpr</replaceable></term>
+
+ <listitem>
+ <para>
+ An expression to be used as default value if the parameter is
+ not specified. The expression has to be convertable to the
+ argument type of the parameter. All parameters after a
+ parameter with default value have to be parameters with default
+ values as well.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
<term><replaceable class="parameter">rettype</replaceable></term>
<listitem>
@@ -667,6 +681,14 @@ COMMIT;
either before or after <replaceable class="parameter">argname</replaceable>.
But only the first way is standard-compliant.
</para>
+
+ <para>
+ The SQL standard does not specify parameter defaults. The syntax
+ with the <literal>DEFAULT</literal> key word is from Oracle, and it
+ is somewhat in the spirit of the standard: SQL/PSM uses it for
+ variable default values. The syntax with <literal>=</literal> is
+ used in T-SQL and Firebird.
+ </para>
</refsect1>
diff --git a/doc/src/sgml/xfunc.sgml b/doc/src/sgml/xfunc.sgml
index a5fb62e18b9..44c83e8dbc7 100644
--- a/doc/src/sgml/xfunc.sgml
+++ b/doc/src/sgml/xfunc.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/xfunc.sgml,v 1.133 2008/10/31 19:37:56 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/xfunc.sgml,v 1.134 2008/12/04 17:51:26 petere Exp $ -->
<sect1 id="xfunc">
<title>User-Defined Functions</title>
@@ -663,6 +663,60 @@ SELECT mleast(VARIADIC ARRAY[10, -1, 5, 4.4]);
</para>
</sect2>
+ <sect2 id="xfunc-parameter-defaults">
+ <title><acronym>SQL</> Functions with Parameters Default Values</title>
+
+ <indexterm>
+ <primary>default values</primary>
+ </indexterm>
+
+ <para>
+ Functions can be declared with parameters with default values or
+ expressions. The default expressions are used as parameter value
+ if the parameter is not explicitly specified in a function call.
+ All parameters after a a parameter with default value have to be
+ parameters with default values as well.
+ </para>
+
+ <para>
+ For example:
+<screen>
+CREATE FUNCTION foo(a int DEFAULT 1, b int DEFAULT 2, c int DEFAULT 3)
+RETURNS int
+LANGUAGE SQL
+AS $$
+ SELECT $1 + $2 + $3;
+$$;
+
+SELECT foo(10, 20, 30);
+ foo
+-----
+ 60
+(1 row)
+
+SELECT foo(10, 20);
+ foo
+-----
+ 33
+(1 row)
+
+SELECT foo(10);
+ foo
+-----
+ 15
+(1 row)
+
+SELECT foo();
+ foo
+-----
+ 6
+(1 row)
+</screen>
+ Instead of the key word <literal>DEFAULT</literal>,
+ the <literal>=</literal> sign can also be used.
+ </para>
+ </sect2>
+
<sect2 id="xfunc-sql-table-functions">
<title><acronym>SQL</acronym> Functions as Table Sources</title>
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-22 06:31:40 +0000