Question

How do you generate a unique, random number to set as the primary key of an object in django?

EDIT – The random number doesn’t have to be the primary key, but it needs to be unique for each object such that I can reference/get/call the object by that number.

Answer 1

Maybe just generate a uuid?

>>> from uuid import uuid4
>>> uid = uuid4()
>>> uid
UUID('88016297-726a-4a42-a5d3-7c1047e27cac')
>>> uid.int
180782199398610579001229174541650132140L
>>> uid.hex
'88016297726a4a42a5d37c1047e27cac'
>>> uid.bytes
'\x88\x01b\x97rjJB\xa5\xd3|\x10G\xe2|\xac'

Long uuid’s are meant to avoid collisions and guarantee within a high degree, uniqueness. If you need a shorter id, this will depend on how you intend to use it. If it needs to be unique across all models because you will use it as a root url, /<slug>/, then it will increase your need to query the database checking for uniqueness before assigning it.

You might want to look at using a slugfield, and a snippet like this which sets a unique slug value on model save.

In a nutshell…long UUID == instant value. Shorter slug value == query loop to confirm uniqueness.