> > Problem is that usually databases aren't very fast to search NULL values > so if you have to for example produce often list of products that you can > buy "infinite amount", you would like to consider using value(s) that don't > conflict from valid set of values.
I'm pretty sure that's not true. +1 to store as Null. On Monday, August 19, 2013 1:07:27 AM UTC-7, Jani Tiainen wrote: > > On Mon, 19 Aug 2013 00:39:09 -0700 (PDT) > Victor Hooi <victo...@gmail.com <javascript:>> wrote: > > > Hi, > > > > I have a Django IntegerField that I'm using to store the purchase limit > for > > a product. > > > > purchase_limit = models.IntegerField() > > > > > > I also need to represent no limit (i.e. infinity) as well in that field. > > > > I was thinking of just using NULL to represent no limit. > > > > purchase_limit = models.IntegerField(blank=True, null=True) > > > > > > Zero would have a meaning for this field (you can't buy any), however > > negative numbers don't have any meaning. > > > > Hence, another option is just to use say, -1 as the value to represent > no > > limit. > > > > Any thoughts on either option, or which one is more "correct"? > > From mathematical point integers forms an infinite (countable) set. Though > in computer science interger is usually a finite set. So what you need is > just define a logic. Note that this also makes impossible to enforce > "unlimited" amount to buy so there will definitely be some maximum amount > you can really buy. > > NULL is usually interpreted as "no value defined" which would suit well in > that sense. Problem is that usually databases aren't very fast to search > NULL values so if you have to for example produce often list of products > that you can buy "infinite amount", you would like to consider using > value(s) that don't conflict from valid set of values. > > I personally would pick max value while leaving NULL to mean "no value > defined". > > -- > > Jani Tiainen > -- 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 django-users+unsubscr...@googlegroups.com. To post to this group, send email to django-users@googlegroups.com. Visit this group at http://groups.google.com/group/django-users. For more options, visit https://groups.google.com/groups/opt_out.
