Subject Re: [IBO] Correct use of transactions for 24x7
Author Kyle Cordes
> I have a small application that is written in Builder 4, using
> IBO3.6 and IB6. The application receives data from an external card-
> reader at a maximum rate of about 5 records per second. This data is
> placed in a single-table database. The client wants to see the last
> 50 records in a grid-type display, updated at least once a second.
> The application also need to approach 24x7 operation.


> I would have liked to close the transaction immediately after
> fetching the data, but then the grid data is cleared - any
> suggestions will be appreciated.

A not-very-IBO-centric suggestion:

Write code to do what you need done, using non-data-aware controls. For
example, you could use a StringGrid to show the user whatever the user
need to see; this could be totally decoupled from the code that posts
and commits the data in to the database. The database writing could
happen in a seperate thread, if desired.

Since 24x7 matters, it might even be worth putting the data capture,
database writing, and GUI in seperate EXE's:

* The data capture software would dump to a file, which could hold data
for a while even if the database is down.

* The database-writing software would read the file and write to the

* the GUI software would refresh/requery the last 50 records from the
database or from the file, as often as desired.

Here an IB / IBO-specific element: you need to make sure that you don't
keep one transaction going "forever".

[ Kyle Cordes * kyle@... * ]
[ Developer, Consultant, Trainer: Java, Delphi, ASTA, etc.]
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