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Default values for function arguments

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Pavel Stehule, with some tweaks by Peter Eisentraut
This commit is contained in:
Peter Eisentraut
2008-12-04 17:51:28 +00:00
parent 7b640b0345
commit 455dffbb73
29 changed files with 2848 additions and 2166 deletions
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26
doc/src/sgml/ref/create_function.sgml
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@ -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>
@ -154,6 +154,20 @@ CREATE [ OR REPLACE ] FUNCTION
</listitem>
</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>
@ -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>