Re: "Cast" SRF returning record to a table type?

On 4/17/15 7:39 PM, David G. Johnston wrote:
> On Friday, April 17, 2015, Jim Nasby <Jim(dot)Nasby(at)bluetreble(dot)com
> <mailto:Jim(dot)Nasby(at)bluetreble(dot)com>> wrote:
>
> I'm working on a function that will return a set of test data, for
> unit testing database stuff. It does a few things, but ultimately
> returns SETOF record that's essentially:
>
> RETURN QUERY EXECUTE 'SELECT * FROM ' || table_name;
>
> Because it's always going to return a real relation, I'd like to be
> able to the equivalent of:
>
> SELECT ... FROM my_function( 'some_table' )::some_table;
>
>
> Unfortunately this means "cast the existing type to some_table" and
> "record" is not a valid type in this context.
>
>
> Is there any trick that would allow that to work? I know that
> instead of 'SELECT * ...' I can do 'SELECT row(t.*) FROM ' ||
> table_name || ' AS t' and then do
>
> SELECT ... FROM my_function( 'some_table' ) AS data( d some_table )
>
> but I'm hoping to avoid the extra level of indirection.
>
> Haven't explored this specific code in depth...but which part - the
> function alias or the select row(t.*)? They seem to be independent
> concerns.

I'm saying that I know I can use the row construct as a poor
work-around. What I actually want though is a way to tell this query:

SELECT ... FROM my_function( 'some_table' )

that my_function is returning a record that exactly matches "my_table".
I suspect there's not actually any way to do that :(
--
Jim Nasby, Data Architect, Blue Treble Consulting
Data in Trouble? Get it in Treble! http://BlueTreble.com