Thread: How to access OLD and NEW with rule on update

Hi,

I need to call a function when updating on a view, like :

create rule udps_upd as on update to udps do
  instead select function_call();

My problem: how do I get a reference to OLD and NEW ?

I tried function_call(OLD, NEW)  -- parse error
  function_call(OLD.oid, NEW.oid)  -- no such attributes
and function_call(OLD.ctid, NEW.ctid).

The last executes, but unfortunately I have no idea how to
proceed in the called function. In all fmgr macros, not one
seems to be concerned with a beast like a tid.

Or is there some information available in the passed
FunctionCallInfoData.context ?

Cheers,

Han Holl

"Han Holl" <han.holl@prismant.nl> writes:
> I need to call a function when updating on a view, like :

> create rule udps_upd as on update to udps do
>   instead select function_call();

> My problem: how do I get a reference to OLD and NEW ?

> I tried function_call(OLD, NEW)  -- parse error

I think you'll need to do it as

    function_call(old.col1, old.col2, ..., new.col1, new.col2, ...)

Pretty tedious :-( but the rule rewriter doesn't support whole-row
references to OLD or NEW.

            regards, tom lane

On Friday 29 November 2002 02:28 am, you wrote:
> "Han Holl" <han.holl@prismant.nl> writes:
> > I need to call a function when updating on a view, like :
> >
> > create rule udps_upd as on update to udps do
> >   instead select function_call();
> >
> > My problem: how do I get a reference to OLD and NEW ?
> >
> > I tried function_call(OLD, NEW)  -- parse error
>
> I think you'll need to do it as
>
>      function_call(old.col1, old.col2, ..., new.col1, new.col2, ...)
>
> Pretty tedious :-( but the rule rewriter doesn't support whole-row
> references to OLD or NEW.
>
Thanks for the info. I was afraid of that.
I't not the tediousness that's the problem though, but that I don't
know the column names. And there might be 300 columns in this
view.
I guess it's read-only for the time being.

Cheers,

Han Holl