James, I agree with you - after thinking about it for another day, your solution would be the best.
Regards, Andréas 2017-10-23 10:51 GMT+02:00 James Schneider <[email protected]>: > > > On Oct 22, 2017 9:29 AM, "Andréas Kühne" <[email protected]> > wrote: > > Hi, > > When you say "globally unique" - I am supposing you mean within your > application? > > What you need to do is set a field to be the primary key, see : > https://docs.djangoproject.com/en/1.11/topics/db/models/#a > utomatic-primary-key-fields > > > Not necessarily. The field only need be unique, but does not need to be > the primary key, and probably shouldn't be IMO. Data (in this case, an > arbitrary ID) should not be used for the internal linkage of the DB. That's > what PK's are for. What if the ID needs to be changed later? All of the > relations would also need to be updated, leading to a large headache at > best. > > > However - it would be simpler to use the standard primary key auto id > field, and then add another field to hold your unique ID in it. This could > then be created on the pre_save signal and you could write something that > randomly generates the unique ID field. See https://docs.djangoproject > .com/en/1.11/topics/signals/ > > > Again, I have to disagree. This shouldn't be a pre_save signal. What > happens when a model save() fails due to a race condition where another > object grabs the ID that was generated in the pre_save signal? The save() > function is likely the best place, or maybe a post_save function that > generates the ID and updates the existing record with a unique ID value. > That way the model can save its data and be 'assigned' an ID as the next > operation. I would personally determine and assign everything in the model > save() function, though, and make it one operation with logic to handle > collisions. > > -James > > -- > You received this message because you are subscribed to the Google Groups > "Django users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/group/django-users. > To view this discussion on the web visit https://groups.google.com/d/ > msgid/django-users/CA%2Be%2BciWFMQsFhgtWeRgLHfObas2Lrwmp > OJ0aw25ePPuajzKgOw%40mail.gmail.com > <https://groups.google.com/d/msgid/django-users/CA%2Be%2BciWFMQsFhgtWeRgLHfObas2LrwmpOJ0aw25ePPuajzKgOw%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Django users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/django-users. To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/CAK4qSCcgvgbaR1cARs%2BOWwnCOeUmJa2G1gjohhfUFLSimybZZw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
