Support UPDATE table SET(*)=...

Hi All,

Please find attached a patch which implements support for UPDATE table1
SET(*)=...
The patch supports both UPDATE table SET(*)=(a,b,c) and UPDATE table1
SET(*)=(SELECT a,b,c FROM...).
It solves the problem of doing UPDATE from a record variable of the same
type as the table e.g. update foo set (*) = (select foorec.*) where ...;

The design is simple. It basically expands the * in transformation stage,
does the necessary type checking and adds it to the parse tree. This allows
for normal execution for the rest of the stages.

Thoughts/Comments?

Regards,

Atri