diff options
Diffstat (limited to 'doc/src/sgml/ref/create_function.sgml')
| -rw-r--r-- | doc/src/sgml/ref/create_function.sgml | 23 |
1 files changed, 19 insertions, 4 deletions
diff --git a/doc/src/sgml/ref/create_function.sgml b/doc/src/sgml/ref/create_function.sgml index 0843a175638..6d7eb84d8f2 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 1.87 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"> |