Hi Claudio,

> >> Oracle way of adding built-in functions seems like better idea to me.
> >> Something like MODIFIED(A, B) returning TRUE if A differs from B
> >> considering null as a special value seems to look better.
> >
> > Now, this could easily be done if we had Stored Functions and
> > typeless parameters ;-)
>
> Do you know who can do this? UDF's, of course. No joke. They can emulate
> typeless input parameters without any engine modification. But their

return

> param type is fixed, although intermediate conversions can happen.

Interesting. How would you do typeless input parameters?

> Problem: there were two types of UDF: value and boolean. The second never
> was implemented but only documented and a "type" field assigned in a

system

> table (for different, prospective UDF types). The parser knows nothing

about

Aha, so that's where TYPE comes from!

> boolean UDF's, too. People would have to live with
> if CHANGED(x, y) = 1
> then ...
> until we implement the boolean type.
>
> The functionality probably can be implemented by an internal UDF, although

a

> good dose of *** code duplication would happen. There would be limitations
> that would make the feature incomplete, unless the engine is told to
> distinguish between built-in UDF's and typical external functions.

With regards,

Martijn Tonies
Database Workbench - developer tool for InterBase, Firebird, MySQL & MS SQL
Server.
Upscene Productions
http://www.upscene.com