Thread

Re: Inability to cast regclass is too restrictive

Oliver Elphick <olly@lfix.co.uk> — 2004-10-09T06:18:56Z

On Sat, 2004-10-09 at 05:35, Tom Lane wrote:
> Oliver Elphick <olly@lfix.co.uk> writes:
> > I tried to use regclass() in a plpgsql function to derive a tablename
> > from its oid so as to build a command string, but I am unable to use the
> > value returned because it cannot be cast to anything.  Therefore I will
> > have to use a complex query on the catalog to do the same work.
> 
> Hmm?  plpgsql is about as permissive as you can get on this point.
> Just assign the result to a variable of the desired type, and it will
> do it if the textual representations are at all compatible.  Example:
> 
> regression=# create function foo(oid) returns text as '
...
> 
> I'm on record that we should allow (explicit) casting to and from text
> for all types, using the types' I/O functions to implement it.  But
> plpgsql already provides essentially that mechanism in its assignment
> operations.  You just hafta do the explicit assignment...

Thanks for the example.  I was trying to do 

  cmd = ''SELECT * FROM '' || regclass(someoid);

-- 
Oliver Elphick                                          olly@lfix.co.uk
Isle of Wight                              http://www.lfix.co.uk/oliver
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