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From:Sinisa Milivojevic Date:June 7 2001 1:17pm
Subject:Re: General Question
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Sharifullah Khan wrote:

>>On 2001 Jun 06, Jani Tolonen <jani@stripped> wrote:
>>>Sharifullah Khan writes:
>>> > I'm a PhD student, new to mySQL and also to this mailing list. I
> defined
>>> > some operators in relational algebra for Selection, Projection, and
>Join to
>>> > compute differential results form a relation. Now I want to implement
>>> > operators in mySQL. I don't know where I start from. I will be very
>>> > full to one who put me on track.
>>>Ps. For the future, if you have general questions about MySQL,
>>>please post them to mysql@stripped.
>>Sharifullah, I think Jani misunderstood your question.  It seems that
>>you want to extend MySQL's syntax with selection, projection and join
>>operators.  If you can give us a brief description of how you would
>>like these operators to work in MySQL, we should be able to direct
>>you to the right parts of the code to be modified.
>Yes, Jani could not understand me. I'm working on continual queries that
>are persistent. A query is evaluated on the whole data at first time. After
>initial evaluation, the query is interested only in updated data. We
>developed differential operators to evaluate the query only on updated data.
>We use a differential relation to store updated data of a relation. The
>operators are evaluated on the differential relation. However, only
>differential relations are not sufficient for Join, because it can need
>existing data.  
>Similar techniques are used for incremental recompuatation of materialised
>views in data warehousing.
>So, We need operators to extract updated data from a relation, to tag
>tuples of updated data differently for  insertion, deletion and
>modification; and to store it in differential relation continously. An
>operator to direct the query to differential relation after initial
>evaluation. The matter is complex for Join, because it needs both
>differential and base relations. At the last, we need operators to compute
>insertion, deletion, or complete result form the differential result of
>differenatial operators.
>This is a brief description of my Project.
>Sharifullah Khan
>School of Computing;
>University of Leeds,
>Leeds LS2 9JT, UK
>Tel#: 0113-233 6788
>Fax#: 0113-233 5468
>Before posting, please check:
>   (the manual)
>           (the list archive)
>To request this thread, e-mail internals-thread859@stripped
>To unsubscribe, e-mail <internals-unsubscribe@stripped>

You can achieve what you need with MySQL by using our TEMPORARY TABLES.

After running first query, create a temporary table out of it and after 
that make LEFT JOIN's with new snapshots over the previous ones.




      ____  __     _____   _____  ___     ==  MySQL AB
     /*/\*\/\*\   /*/ \*\ /*/ \*\ |*|     Sinisa Milivojevic
    /*/ /*/ /*/   \*\_   |*|   |*||*|     mailto:sinisa@stripped
   /*/ /*/ /*/\*\/*/  \*\|*|   |*||*|     Larnaca, Cyprus
  /*/     /*/  /*/\*\_/*/ \*\_/*/ |*|____
             /*/             \*\                Developers Team

General QuestionSharifullah Khan6 Jun
  • General QuestionJani Tolonen6 Jun
    • Re: General QuestionTimothy Smith6 Jun
      • Re: General QuestionSharifullah Khan7 Jun
    • Re: General QuestionSinisa Milivojevic7 Jun