Hi Ian, I see that Massimo has answered you, but on re-reading your question I wasn't clear quite what you were asking. I have an application that needs to use UUIDs myself, so thought it worth jumping in.
On 14/05/14 16:44, Ian W. Scott wrote: > I need to take an existing db and implement a UUID referencing system so > that I can sync local db's with a central remote version. But I'm > concerned that this will break reference fields that refer to the newly > synced rows. > Is this an existing web2py-generated db, or a legacy db? Am assuming the former, but tell me if I'm wrong... Do you have existing ID fields which you wish to /convert/ to UUIDs, so that you are using UUIDs *instead* of IDs? Or are the IDs exposed in the application, such that you wish to /supplement/ them with an UUID field to support replication? > My understanding is that the UUID field is necessary because a csv > import will assign different row ids to the new entries in the target db > than the ones they had in the source db (especially if new records have > been added to the target db in the meantime). The UUID is supposed to > overcome this, by allowing the db to recognize that rows are equivalent > even if they have different ids. But in that case, won't reference > fields in other tables often be pointing to the wrong ID number in the > target db? (i.e., they'll keep the row ID of the db version in which > they were created, and if this ID changes in the target db they will > then be referencing a different record.) > It's the mention of CSV imports that I'm stuck on - is the intention to use this as your replication mechanism, or are you saying that you are importing data into each instance of the db, and need to preserve imported IDs? I may be misreading you, but I would very strongly recommend the use of the db's existing native replication mechanism if at all possible. You don't specify your back-end database, but we've had good results from Postgres replication, FWIW. > Sorry if this explanation is overly complicated. I'm just trying to get > things clear in my own mind. > It does sound complicated, but I'm not 100% certain that I'm clearly distinguishing between the outcome you want and your thoughts as to how to achieve it. FWIW, I have a similar issue, and what I would like to do is use UUID PKs throughout in web2py, and use the db's *native* replication mechanism, which should work OOTB with UUID PKs. Am I right in thinking that this approach would solve your ID/replication problem, but that your situation is complicated by the fact that your starting point is an existing app with IDs? Apologies for bombarding you with questions! -- Regards, PhilK 'a bell is a cup...until it is struck' -- Resources: - http://web2py.com - http://web2py.com/book (Documentation) - http://github.com/web2py/web2py (Source code) - https://code.google.com/p/web2py/issues/list (Report Issues) --- You received this message because you are subscribed to the Google Groups "web2py-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to web2py+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
