Re: CREATE ROUTINE MAPPING

On Fri, Jan 12, 2018 at 11:11:26AM -0500, Corey Huinker wrote:
> >
> > PostgreSQL allows function overloading, which means that there can
> > be multiple functions with same name differing in argument types.
> > So, the syntax has to include the input parameters or their types
> > at least.
>
> "local_routine_name" and "remote_routine_spec" were my own
> paraphrasings of what the spec implies. I'm nearly certain that the
> local routine name, which the spec says is just an identifier,
> cannot have a parameter spec on it, which leaves only one other
> place to define it, remote_routine_spec, which wasn't defined at
> all. I _suppose_ parameter definitions could be pushed into options,
> but that'd be ugly.

In my draft of SQL:2011, which I don't think has substantive changes
to what's either in the official SQL:2011 or SQL:2016, it says:

<routine mapping definition> ::=
CREATE ROUTINE MAPPING <routine mapping name> FOR <specific routine designator>
SERVER <foreign server name> [ <generic options> ]
Syntax Rules
1) Let FSN be the <foreign server name>. Let RMN be the <routine mapping name>.
2) The catalog identified by the explicit or implicit catalog name of FSN shall include a foreign server
descriptor whose foreign server name is equivalent to FSN.
3) The SQL-environment shall not include a routine mapping descriptor whose routine mapping name is
RMN.
4) Let R be the SQL-invoked routine identified by the <specific
routine designator>. R shall identify an SQL-invoked regular function.

It goes on from there, but I think there's a reasonable interpretation
of this which allows us to use the same syntax as CREATE
(FUNCTION|PROCEDURE), apart from the body, e.g.:

CREATE ROUTINE MAPPING local_routine_name
FOR (FUNCTION | PROCEDURE) remote_routine_name ( [ [ argmode ] [ argname ] argtype [ { DEFAULT | = } default_expr ] [, ...] ] )
[ RETURNS rettype
| RETURNS TABLE ( column_name column_type [, ...] ) ]
SERVER foreign_server_name
[ (option [, ...]) ]

Does that seem like too broad an interpretation?

Best,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778

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