Re: feature & performance comparison

From: Mark Townsend <markbtownsend_at_home.com>
Date: Mon, 11 Jun 2001 04:46:18 GMT
Message-ID: <B7499B2A.153BE%markbtownsend@home.com>

in article B7498743.15384%markbtownsend_at_home.com, Mark Townsend at markbtownsend_at_home.com wrote on 6/10/01 8:21 PM:

The PDF link works OK, however. This IS cool, it's a nicely orthogonal syntax. I checked the Oracle9i doc and it seems that a named subquery cannot reference it's own name, so I guess Oracle doesn't do this this way (although CONNECT BY does provide equivalent capability - restrictions may be different however).

See Serge - I CAN give credit where credit is due :-)

> in article 3B243445.E53F5D19_at_ca.ibm.com, Blair Kenneth Adamache at
> adamache_at_ca.ibm.com wrote on 6/10/01 8:00 PM:
>

>> See appendix M of the SQL Reference, at this page: >>
http://www-4.ibm.com/cgi-bin/db2www/data/db2/udb/winos2unix/support/v7pubs.d 2>> w

>> /en_main

>
> Cheers - but, um, we have a problem Houston. Trying to access the HTMl
> version I get the following error message
>
> DTWF019E: Net.Data failed to connect to a backend The Net.Data ODBC language
> environment could not allocate the environment handle.
>
> Planned downtime, right :-)
>

>> There are three examples, and it talks about controlling depth. Recursive SQL
>> has been in DB2 since 1995.
>> 
>> Mark Townsend wrote:
>> 
>>> in article B749727F.1536B%markbtownsend_at_home.com, Mark Townsend at
>>> markbtownsend_at_home.com wrote on 6/10/01 6:52 PM:
>>> 
>>>>> WITH RPL (PART, SUBPART, QUANTITY) AS
>>>>> (  SELECT ROOT.PART, ROOT.SUBPART, ROOT.QUANTITY
>>>>> FROM PARTLIST ROOT
>>>>> WHERE ROOT.PART = '01'
>>>>> UNION ALL
>>>>> SELECT CHILD.PART, CHILD.SUBPART, CHILD.QUANTITY
>>>>> FROM RPL PARENT, PARTLIST CHILD
>>>>> WHERE  PARENT.SUBPART = CHILD.PART
>>>>> )
>>>>> SELECT DISTINCT PART, SUBPART, QUANTITY
>>>>> FROM RPL
>>>>> ORDER BY PART, SUBPART, QUANTITY
>>> 
>>> Hmm - actually, there is more to this than I first saw - presumably this
>>> iterates down through all levels of child ? How is this transformed ? Can
>>> you push predicates into the traversal ? This may be way cool.
>> 

>
  Received on Sun Jun 10 2001 - 23:46:18 CDT