Subject: Re: Are we losing momentum?
From: Rod Taylor <rbt@rbt.ca>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: sailesh@cs.berkeley.edu, "scott.marlowe" <scott.marlowe@ihs.com>,
	Shridhar Daithankar <shridhar_daithankar@persistent.co.in>,
	PostgreSQL Hackers <pgsql-hackers@postgresql.org>
In-Reply-To: <25012.1051223307@sss.pgh.pa.us>
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Date: 24 Apr 2003 19:14:02 -0400

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On Thu, 2003-04-24 at 18:28, Tom Lane wrote:
> 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?
>=20
> > Why extensions, even for things like indexes that aren't in the
> > standard, they create views (SYSCAT.INDEXES, SYSCAT.INDEXAUTH etc.)=20
> > ...
> > 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.
>=20
> > 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.
>=20
> 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.

We could probably get away with adding pg_ views to the information
schema though.   For extensions of an existing view, simply inherit the
real view into a pg_ labelled view and add the new columns.

--=20
Rod Taylor <rbt@rbt.ca>

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