On Tue, Jun 26, 2001 at 05:11:47PM -0400, Alex Pilosov wrote:
> I started thinking about Tom's idea to implement functions as table
> source.
>
> To me, it seems that a very few changes are necessary:
> a) parser must be changed to allow functioncall to be a table_ref
> (easy)
>
> b) when a Query node is generated out of such a call "select * from foo()"
> it should be almost identical to one generated out of "select * from
> (select * from foo)" with one distinction: list of query attributes should
> be completed based on return type of foo().
For the result from foo() you must somewhere define attributes (names).
Where? In CREATE FUNCTION statement? Possible must be:
select name1, name2 from foo() where name1 > 10;
What returns foo()? ...the pointer to HeapTuple or something like this or
pointer to some temp table?
> c) executor should support execution of such Query node, properly
> extracting things out of function's return value and placing them into
> result attributes.
d) changes in fmgr
e) SPI support for table building/filling inside foo()
IMHO very cool and nice feature, but not easy for imlementation.
Karel
-- Karel Zak <zakkr@zf.jcu.cz>http://home.zf.jcu.cz/~zakkr/C, PostgreSQL, PHP, WWW, http://docs.linux.cz,
http://mape.jcu.cz