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From:Sharifullah Khan Date:June 7 2001 8:57am
Subject:Re: General Question
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>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

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