> I'm writing an application which will hold a database of people. Ofcourse, > people can have the same name, so I want to stock them with an unique ID. > > I've searched and found some things: > - uuid.uuid4() > - id(name) > - os.urandom(n) > > But they seem overkill to me. Well, maybe not id(). > > What should I use the best for this? Maybe examples of other programs that > do something alike?
Use the auto-increment feature of your database database management backend. (Assuming you're using a database backend like MySQL, postgresql, etc.) In MySQL your database description would look something like this (with any other fields you need): # MySQL table description: CREATE TABLE IF NOT EXISTS mytable ( `uid` BIGINT unsigned NOT NULL auto_increment unique, `uname` CHAR(32) NOT NULL default "guest", PRIMARY KEY (`uid`)); You could use MySQLdb (third party python module) to talk to the MySQL process with Python. Other database managers have similar abilities. >> os.urandom(n) Random numbers are random, NOT unique. If you're using your own backend, like a text file or whatever, stop. Take the time to learn to use a database manager like postgresql or MySQL or whatever. They have already solved many of the problems you're now facing. It will be well worth the time and frustration. Otherwise, you'll have to parse your database and get the previously used value and then increment that. However, this solution will fail if there are multiple processes, or threads accessing the data concurrently. To solve that problem you'll have to introduce some manner of mutex to gurantee that only one process has access to the unique data at any given time. Things get complicated. All of these problems have already been solved with other database managers. Use them! In a pinch, with a low volume database for non-critical data, you could probably get away with using a Unix epoch style timestamp with sufficient granularity. But even this is in no way, "guaranteed" to be unique. It's just, "probably unique". It would look like this: >>> import time >>> time.time() 1256796357.661967 If it absolutely must be unique, use a database manager that can make that guarantee. Best of luck! -Modulok- _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
