Re: ALTER TABLE should change respective views

From: Tom Lane <tgl@sss.pgh.pa.us>
Subject: Re: [HACKERS] ALTER TABLE should change respective views
To: "Peter Eisentraut" <peter_e@gmx.net>
Cc: pgsql-hackers@postgresql.org, "Archana Sundararam" <archnasr@yahoo.com>
Date: Tuesday, May 5, 2009, 8:10 AM

Peter Eisentraut <peter_e@gmx.net> writes:
> And this could then also change the return type of foo(), thus changing the
> row type of the view and would thus propogate up to other views.  And so if
> you have "many views", as you say, this could become a great mess.  You could
> probably define and implement a solution, but it would be very confusing and
> risky to use.

The SQL committee has also historically chosen to punt on such things.
Note the long-established rule that "*" is expanded at view definition
time (so adding columns doesn't change views).  I also see a flat
prohibition on *any* view reference in the newly added SET DATA TYPE
command (SQL:2008 11.17 <alter column data type clause>):

7) C shall not be referenced in the <query expression> of any view descriptor.

            regards, tom lane