diff options
Diffstat (limited to 'doc/src/sgml/ref/create_function.sgml')
| -rw-r--r-- | doc/src/sgml/ref/create_function.sgml | 32 |
1 files changed, 22 insertions, 10 deletions
diff --git a/doc/src/sgml/ref/create_function.sgml b/doc/src/sgml/ref/create_function.sgml index 5de4967789d..639647eab3c 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 1.82 2008/12/04 17:51:26 petere Exp $ +$PostgreSQL: pgsql/doc/src/sgml/ref/create_function.sgml,v 1.83 2008/12/18 18:20:33 tgl Exp $ --> <refentry id="SQL-CREATEFUNCTION"> @@ -21,7 +21,7 @@ $PostgreSQL: pgsql/doc/src/sgml/ref/create_function.sgml,v 1.82 2008/12/04 17:51 <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> [ { DEFAULT | = } <replaceable class="parameter">defexpr</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> @@ -37,7 +37,7 @@ CREATE [ OR REPLACE ] FUNCTION [ WITH ( <replaceable class="parameter">attribute</replaceable> [, ...] ) ] </synopsis> </refsynopsisdiv> - + <refsect1 id="sql-createfunction-description"> <title>Description</title> @@ -133,7 +133,7 @@ CREATE [ OR REPLACE ] FUNCTION <listitem> <para> - The data type(s) of the function's arguments (optionally + The data type(s) of the function's arguments (optionally schema-qualified), if any. The argument types can be base, composite, or domain types, or can reference the type of a table column. </para> @@ -160,10 +160,11 @@ CREATE [ OR REPLACE ] FUNCTION <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. + not specified. The expression has to be coercible to the + argument type of the parameter. + Only input (including <literal>INOUT</>) parameters can have a default + value. All input parameters following a + parameter with a default value must have default values as well. </para> </listitem> </varlistentry> @@ -173,7 +174,7 @@ CREATE [ OR REPLACE ] FUNCTION <listitem> <para> - The return data type (optionally schema-qualified). The return type + The return data type (optionally schema-qualified). The return type can be a base, composite, or domain type, or can reference the type of a table column. Depending on the implementation language it might also be allowed @@ -497,6 +498,18 @@ CREATE FUNCTION foo(int, out text) ... </para> <para> + Functions that have different argument type lists will not be considered + to conflict at creation time, but if defaults are provided they might + conflict in use. For example, consider +<programlisting> +CREATE FUNCTION foo(int) ... +CREATE FUNCTION foo(int, int default 42) ... +</programlisting> + A call <literal>foo(10)</> will fail due to the ambiguity about which + function should be called. + </para> + + <para> When repeated <command>CREATE FUNCTION</command> calls refer to the same object file, the file is only loaded once per session. To unload and @@ -664,7 +677,6 @@ COMMIT; </refsect1> - <refsect1 id="sql-createfunction-compat"> <title>Compatibility</title> |