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Support use of function argument names to identify which actual arguments

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match which function parameters.  The syntax uses AS, for example
	funcname(value AS arg1, anothervalue AS arg2)

Pavel Stehule
This commit is contained in:
Tom Lane
2009-10-08 02:39:25 +00:00
parent 2eda8dfb52
commit 717fa274d1
34 changed files with 1925 additions and 274 deletions
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23
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 1.87 2009/10/02 18:13:04 tgl Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/create_function.sgml,v 1.88 2009/10/08 02:39:14 tgl Exp $
-->
<refentry id="SQL-CREATEFUNCTION">
@ -65,7 +65,7 @@ CREATE [ OR REPLACE ] 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 recreate the function. (When using <literal>OUT</>
parameters, that means you cannot change the names or types of any
parameters, that means you cannot change the types of any
<literal>OUT</> parameters except by dropping the function.)
</para>
@ -121,8 +121,11 @@ CREATE [ OR REPLACE ] FUNCTION
<para>
The name of an argument. Some languages (currently only PL/pgSQL) let
you use the name in the function body. For other languages the
name of an input argument is just extra documentation. But the name
of an output argument is significant, since it defines the column
name of an input argument is just extra documentation, so far as
the function itself is concerned; but you can use input argument names
when calling a function to improve readability (see <xref
linkend="sql-syntax-calling-funcs">). In any case, the name
of an output argument is significant, because it defines the column
name in the result row type. (If you omit the name for an output
argument, the system will choose a default column name.)
</para>
@ -570,6 +573,18 @@ CREATE FUNCTION foo(int, int default 42) ...
to replace it (this includes being a member of the owning role).
</para>
<para>
When replacing an existing function with <command>CREATE OR REPLACE
FUNCTION</>, there are restrictions on changing parameter names.
You cannot change the name already assigned to any input parameter
(although you can add names to parameters that had none before).
If there is more than one output parameter, you cannot change the
names of the output parameters, because that would change the
column names of the anonymous composite type that describes the
function's result. These restrictions are made to ensure that
existing calls of the function do not stop working when it is replaced.
</para>
</refsect1>
<refsect1 id="sql-createfunction-examples">