>Hi,
> I have a table which store the last ID generated for my invoise. It will be access and updated by every user.
>I have a problem that, what type of buffering should be used for this if only this record will be used for ID generation?
> How to re-use the ID if some body cancel the ID before inserted?
>
>Thank you

Don't use any buffering on your Keys table. If you need to reuse an ID, keep it in a sepatate table of unused IDs. Ideally, you don't assign this number until they actually save.