X-Original-To: pgsql-hackers@postgresql.org Received: from spampd.localdomain (postgresql.org [64.49.215.8]) by postgresql.org (Postfix) with ESMTP id 1EFB1475B85 for ; Thu, 24 Apr 2003 18:13:21 -0400 (EDT) Received: from datafix.CS.Berkeley.EDU (datafix.CS.Berkeley.EDU [128.32.37.185]) by postgresql.org (Postfix) with ESMTP id D9214475B85 for ; Thu, 24 Apr 2003 18:12:49 -0400 (EDT) Received: (from sailesh@localhost) by datafix.CS.Berkeley.EDU (8.11.6/8.11.6) id h3OMCl416061; Thu, 24 Apr 2003 15:12:47 -0700 X-Authentication-Warning: datafix.CS.Berkeley.EDU: sailesh set sender to sailesh@cs.berkeley.edu using -f Reply-To: sailesh@cs.berkeley.edu X-URL: http://www.cs.berkeley.edu/~sailesh X-Attribution: Sailesh To: Rod Taylor Cc: "scott.marlowe" , Shridhar Daithankar , PostgreSQL Hackers Subject: Re: Are we losing momentum? References: <1051189596.46146.24.camel@jester> From: Sailesh Krishnamurthy Date: 24 Apr 2003 15:12:47 -0700 In-Reply-To: <1051189596.46146.24.camel@jester> Message-ID: Lines: 38 User-Agent: Gnus/5.0808 (Gnus v5.8.8) XEmacs/21.1 (Cuyahoga Valley) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Spam-Status: No, hits=-24.0 required=5.0 tests=BAYES_01,IN_REP_TO,REFERENCES,USER_AGENT_GNUS_UA, X_AUTH_WARNING autolearn=ham version=2.50 X-Spam-Level: X-Spam-Checker-Version: SpamAssassin 2.50 (1.173-2003-02-20-exp) X-Archive-Number: 200304/868 X-Sequence-Number: 38358 >>>>> "Rod" == Rod Taylor writes: >> This is exactly the reason why in db2 _no_ guarantees are made >> regarding the constancy of the system catalogs (that are in the >> SYSIBM schema). Instead, the equivalent views (in the SYSCAT >> schema) are _never_ broken (whether in a point release or a new >> version). In fact, the SYSCAT views correspond to the ISO SQL >> standard. 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? Yes, the INFO SCHEMA - thankfully it's long enough since I looked at the SQL specs .. I've started forgetting terms. If I never have to write or read any spec material again, it won't be too soon. Why extensions, even for things like indexes that aren't in the standard, they create views (SYSCAT.INDEXES, SYSCAT.INDEXAUTH etc.) Rod> I'm going with the assumptions DB2 has extended SQL specs in Rod> some shape or form. 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. -- Pip-pip Sailesh http://www.cs.berkeley.edu/~sailesh