Re: Best approach for a "gap-less" sequence

In article <878xlrwcxm.fsf@gmail.com>,
Jorge Godoy <jgodoy@gmail.com> writes:

> AgentM <agentm@themactionfaction.com> writes:
>> Since the gapless numbers are purely for the benefit of the tax people, you
>> could build your db with regular sequences as primary  keys and then regularly
>> (or just before tax-time) insert into a table  which maps the gapless sequence
>> to the real primary key.

> That's also an interesting approach.  An auxiliary table like

>        transaction integer FK to the transactions table
>        transaction_nb integer  gapless sequence

> should do it.  A trigger inserting on this auxiliary table would also take
> care of everything...  If I have an after trigger I believe I wouldn't need
> any locking...  I have to think about this...

Why putting gapless numbers into the database at all?  Just calculate them at
query time.