sequence omits numbers?

Hi there,

I have encountered a strange problem: a sequence seems to leave out numbers - how can that happen?

But let me describe the setup briefly:
For out internal online ordering system I use a function (stored in db, lets call it new_number()) that creates new invoice numbers. These have to be unique so new_number() fetches a new number from a sequence for each invoice number.
The whole application consists of a few webpages based on php using the pear db.php to communicate with our oracle 8i server. Each time a user creates a new invoice new_number() is called in order to supply a new number. (it is only possible to get a new number once, so there is no problem with the 'reload' button of the browser) Everything is logged so that I can review which user has created which new invoice-number etc.
When everything is ok, the numbers have no gaps inbetween, but sometimes there are small gaps (3 or 4 numbers missing) and even large gaps (30-50 numbers missing).

I have no idea how that can happen especially because I log each call of the new_number() function in my php-scripts... In order to troubleshoot that I first had a trigger in mind that fires when the function is called but since that is not possible I have no further idea how to find the error. Any ideas?

Stefan

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Stefan Röhle
Zentrum für Datenverarbeitung
Johannes Gutenberg-Universität
D-55099 Mainz
Germany

Tel. +49-(0)6131/39-26303
Fax. +49-(0)6131/39-26407
Email: roehle_at_uni-mainz.de


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