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Re: Using dimensions

From: Tanel Poder <tanel.poder.003_at_mail.ee>
Date: Tue, 30 Sep 2003 18:39:29 -0800
Message-ID: <F001.005D18BF.20030930183929@fatcity.com>


Using dimensionsHm, I did a brief check and it seems I was a bit wrong: Dimensions are required only when you want query rewrite to use materialized views computed on other constraints&relationships than primary/foreign/unique keys. If you want to use your custom relationships in rewrites, you have to use dimensions.

That's at least what I understood from docs:

http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96520/qr.htm#721

Check "trusted" parameter under "Accuracy of query rewrite"

Sorry for misinformation and if you get different understanding docs, please post it here :) Tanel

  Got a link for this requirement in the manual?

  Raj
    -----Original Message-----
    From: Tanel Poder [mailto:tanel.poder.003_at_mail.ee]     Sent: Tuesday, September 30, 2003 4:50 AM     To: Multiple recipients of list ORACLE-L     Subject: Re: Using dimensions

    Query rewriting to use materialized views requires dimensions to be defined.

    Tanel.

      Thanks Scott, okay lets forget OLTP .. but I haven't seen any _actual_ uses of dimensions ... where does one use them? in SQLs?

      I have scanned TFM, but haven't STFW'd yet ... scared of too many hits.

      Thanks
      Raj
      -------------------------------------------------------------------------------- 
      Rajendra dot Jamadagni at nospamespn dot com 
      All Views expressed in this email are strictly personal. 
      QOTD: Any clod can have facts, having an opinion is an art ! 

-----Original Message-----
From: Scott Canaan [mailto:srcdco_at_rit.edu] Sent: Monday, September 29, 2003 11:55 AM To: Multiple recipients of list ORACLE-L Subject: RE: Using dimensions Dimensions are data warehouse constructs. They are implemented as tables in the database, but have the characteristic of a hierarchy that can be traversed. For example: a time dimension can have the hierarchy of date, day, week, month, quarter, year, decade, century. This is used for rollup reporting within the data mart. I don't see any good use of it in an OLTP environment, but I may be wrong. Scott Canaan (srcdco_at_rit.edu) (585) 475-7886 "Life is like a sewer, what you get out of it depends on what you put into it." - Tom Lehrer.
-----Original Message-----
From: Jamadagni, Rajendra [mailto:Rajendra.Jamadagni_at_espn.com] Sent: Monday, September 29, 2003 10:55 AM To: Multiple recipients of list ORACLE-L Subject: Using dimensions I have tried, but haven't found a good example of how to _use_ a dimension in 9ir2. I defined one, but then sat clueless on what to do with it. Is it any good in an OLTP environment? (I smell the answer is a NO, but still) ... Any notes from your experience? TIA Raj
--------------------------------------------------------------------------------
Rajendra dot Jamadagni at nospamespn dot com All Views expressed in this email are strictly personal. QOTD: Any clod can have facts, having an opinion is an art !
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Author: Tanel Poder
  INET: tanel.poder.003_at_mail.ee

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Received on Tue Sep 30 2003 - 21:39:29 CDT

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