Hi, how can I let the database generate a generally unique id(guid, String)? Thanks, Tamara
2011/10/27, Simon Slavin <slav...@bigfraud.org>: > > On 27 Oct 2011, at 10:04pm, Kees Nuyt wrote: > >> On Thu, 27 Oct 2011 21:47:17 +0100, Simon Slavin >> <slav...@bigfraud.org> wrote: >> >>> On 27 Oct 2011, at 8:12pm, Tim Streater wrote: >>> >>>> Is there a way to get a unique id from a database >>>> without actually creating a new row? >>> >>> Sure. Do something like >>> >>> SELECT max(id) FROM mytab; >>> >>> Then in your own code, add 1 to it and use that as >>> the "id" for the row you're about to save. >>> Make sure you handle the NULL case (where mytab >>> doesn't have any rows in it yet) correctly. >> >> And wrap it all in an IMMEDIATE or EXCLUSIVE transaction, or >> you'll get a race condition if some other process tries to do the >> same at the same time. > > Oh right. Yes, if you have more than one process doing this at the same > time, you're screwed. Better just to pick a random integer out of a huge > range and use that. > > Simon. > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > -- Gesendet von meinem Mobilgerät _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
