Fidel,

F> 1) The Invoice numbers have to be sequential, and no gaps are allowed
F> 2) There shall not exist a case where invoice2.timesaved >
F> invoice1.timesaved and invoice1.no > invoice2.no

F> In the demo I have created, this is no problem. If the transaction
F> fails, then I can always move the sequence back a number using
F> ALTER SEQUENCE SEQ_NAME RESTART WITH GEN_ID(SEQ_NAME, 0)-1. Now, on
F> the concurrent version, that will, obviously, not work. I could use
F> locking, but I don't think that is the best approach.

F> Can someone suggest a good approach to solve this?

I wouldn't use sequences for that. Serialization is required here,
IMHO.

Ciao
--
Nando Dessena
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