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TadoDataset with child

edited July 2008 in RAP
I am revisiting the use of TadoDatasets and ReportBuilder. Some time ago, I
found reports with paramertized queries (master/detail) were extremely
slow. The solution, as I recall, was to select ALL child records and order
that result set by the parameter value. Because there are a hundred thousand
records in the child table, I abandoned TadoDatasets in favor of Ttables
(which my database also supports).

Because we want to open reports to end users, including modification of
queries, I want to use parameterized queries (eg, select * from Orders where
CustomerID = :CustomerID).

I tested on a pretty simple report but it takes 40 secs to generate 15
pages. Yikes!

The last reading I have on this topic is a TechNote authorized by Nard dated
Wed, 12 Apr 2006 with the subject " master detail crawls at slow speed".

Perhaps there is some newer thinking on this?




  • edited July 2008

    Then this would probalby not normally be posted under .RAP :-)

    don't know how many records you have, or what events you have tied to the
    tables (e.g. AfterScroll even may slow things down).

    I don't have enough info on your UI, but if you are not using RB's DADE, and
    you are looking for purly speed, create TLists (or most probalby
    TObjectLists) of your data and use TJIPPipelines. I've done this and it
    makes things a lot faster--none of the overhead of the TDataset.

    Ed Dressel
    Team DM
  • edited July 2008
    sorry for the mis-post; i'll post more detail in proper group.


  • edited July 2008

    Selecting All records is slow, we do not recommend that. I think you

    Most SQL database engines only support SQL. Using a Table object, results in
    a Select All records.

    Best solution is to use DADE, which can generate special linking SQL
    automatically for you.

    When using external datasets, you can write your own SQL to support
    DataPipeline linking. Using DataPipeline linking requires that you select
    all the detail records that will be used in the report. For any search
    criteria in the master, you have to also apply the criteria to the detail -
    DADE does this for you.

    Nard Moseley
    Digital Metaphors

    Best regards,

    Nard Moseley
    Digital Metaphors
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