Django中不区分大小写的字段

Question

Currently, I have a Django project containing a model called Event which has several properties, one of them being full_name .

from django.db import models


class Event(models.Model):
    description = models.CharField(blank=False, max_length=200)
    full_name = models.CharField(blank=False, null=True, max_length=200, unique=True)

What I want to acchieve is to prevent users from making two events in which one would be called MyEvent and the other would be called myevent , so I want the name to not be case sensitive. Furthermore, I come from a country with some funny letters, like š . Users are so used to computer systems not supporting these letters that I want to also prevent the existance of two events, one called šoo and the other soo .

Basically, I have a function myfunction and want to have a model constraint such that for each instance of the model, the value myfunction(instance.full_name) is unique.

My first idea, which sort of works, is to have a model form with a clean full name function:

def clean_full_name(self):
    return myfunction(self.cleaned_data.get('full_name'))

This works. However, I now have a view in which I want to display the full names of all events, and here, I want to display the original names. Using my approach, this is impossible (the funcion is one-way only). Is there an elegant solution to this?

Answer 1

You can have another field which is basically the slug of the name. Infact, I believe it is not a good idea to have the name as a unique field (but i should clarify that i do not know your requirement).

Basically, the validation on the slug field ensures uniqueness . Also, you can just keep the slug field hidden from all forms, etc..

Example:

>>> from django.utils.text import slugify
>>> slugify(u"śtack Overflow")
u'stack-overflow'
>>> slugify(u"stack Overflow")
u'stack-overflow'
>>> slugify(u"stack  Overflow")
u'stack-overflow'
>>> slugify(u"stack \t Overflow")
u'stack-overflow'
>>> slugify(u"stack \n Overflow")
u'stack-overflow'

A few of these combinations map to the same slug - which ensures uniqueness for the broad usecases.

Answer 2

An idea would be to implement a case insensitive unique constraint on the field.

Possible answers in:

• Case insensitive unique model fields in Django?
• Unique model field in Django and case sensitivity (postgres)

Answer 3

Just save both full_name and clean_full_name in the database, and make clean_full_name unique.

You can validate the full_name field by putting the validation code in a property setter. Have a look at this blog for details.