On Tue, Nov 22, 2011 at 3:52 PM, Merlin Moncure <mmoncure@xxxxxxxxx> wrote: > On Tue, Nov 22, 2011 at 2:43 PM, David Johnston <polobo@xxxxxxxxx> wrote: >> Just create a single sequence for each year and then call the proper one >> on-the-fly. You can create multiple sequences in advance and possible even >> auto-create the sequence the first time one is attempted to be used in a >> given year. If you can live with possible (but probably unlikely) gaps in >> the sequence then all the concurrency will be handled for you and you can >> focus on writing a function that, given a year, will return the proper >> value. > > I personally think the 'record the next to be inserted value' in a > table somewhere is better unless you are trying to support a lot of > concurrent operations. Also the gap issue is more likely to come up > than you're letting on -- a rolled back transaction is all it takes. Yeah, using a table seems to have the advantage of being about the only thing that would work, though I think row_number properly used (with an invariant ordering and no deletes) also works. -kenneth -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
