To: sailesh@cs.berkeley.edu
Cc: Rod Taylor <rbt@rbt.ca>, "scott.marlowe" <scott.marlowe@ihs.com>,
	Shridhar Daithankar <shridhar_daithankar@persistent.co.in>,
	PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Subject: Re: Are we losing momentum? 
In-reply-to: <bxyist3k0io.fsf@datafix.CS.Berkeley.EDU> 
References: <Pine.LNX.4.33.0304230922450.12251-100000@css120.ihs.com>
	<bxyadeg1m3j.fsf@datafix.CS.Berkeley.EDU>
	<1051189596.46146.24.camel@jester>
	<bxyist3k0io.fsf@datafix.CS.Berkeley.EDU>
Comments: In-reply-to Sailesh Krishnamurthy <sailesh@cs.berkeley.edu>
	message dated "24 Apr 2003 15:12:47 -0700"
Date: Thu, 24 Apr 2003 18:28:27 -0400
Message-ID: <25012.1051223307@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

Sailesh Krishnamurthy <sailesh@cs.berkeley.edu> writes:
>     Rod> The INFORMATION_SCHEMA?  Out of curiousity, how do they
>     Rod> handle DB2 extensions?  Do they create new views in that
>     Rod> schema?  Do they ignore them?

> Why extensions, even for things like indexes that aren't in the
> standard, they create views (SYSCAT.INDEXES, SYSCAT.INDEXAUTH etc.) 
> ...
> Certainly - it's just that the meaning and number of existing columns
> and rows in the syscat views are always backward compatible. That
> includes support of the info schema - for the sql standard features
> that db2 supports.

> So if there's something new in the catalog tables that is a result of
> an extension and doesn't appear as a column in the syscat views (or
> the info schema) then an appropriate column may be added to the view -
> provided that this doesn't break the info schema compatibility.

Of course, IBM can afford to keep reps on the SQL standards committee to
make sure that no future spec extension conflicts with the names they've
used for their additions to INFORMATION_SCHEMA.  We, on the other hand,
could easily get burnt by spec changes.

			regards, tom lane