I liked the idea at first but after couple tests realized that the it will
alway raise the error on save().
The problem is that I can't add any Email without Person, this looks great
but, I also can't add a Person without an Email and so it will never allow
me to add anything.
Maybe I should keep it as ForeignKey but ensure that the Email is filled
just in the form validation, not on database/class level? Following a test
that i did:
>>> p = Person()
>>> p.first_name = 'aaa'
>>> p.last_name = 'bbb'
<Person: bbb, aaa>
>>> p.emails.all()
[]
>>> p.emails.count()
0
>>> p.emails.create(email='a...@aaa.aaa')
Traceback (most recent call last):
File "<console>", line 1, in <module>
...
(value, self.field.rel.to._meta.object_name)
ValueError: Cannot assign "<Person: bbb, aaa>": "Member" instance isn't
saved in the database.
>>> p.save()
Traceback (most recent call last):
File "<console>", line 1, in <module>
...
raise ValueError('Need at least one e-mail.')
ValueError: Need at least one e-mail.
On Wednesday, April 8, 2015 at 11:38:28 AM UTC-4, Bruno A. wrote:
> +1 for Javier's answer, use a simple Foreign key on the e-mail field, not
> a ManyToMany on the Person (M2M allows an email to belong to multiple
> users). The Foreign key ensures an e-mail belongs to only 1 user, and that
> 2 users cannot have the same e-mail, but lets a user have multiple.
>
> To force all users to have at least one e-mail, something like this would
> do the job:
>
> class Person(models.Model):
> first_name = models.CharField(max_length=100)
> last_name = models.CharField(max_length=100)
>
> def save(self, *args, **kwargs):
> if self.emails.count() == 0:
> raise ValueError("Need at least one email.")
> return super(Person, self).save(*args, **kwargs)
>
>
> class Email(models.Model):
> person = models.ForeignKey(Person, related_name='emails')
> email = models.EmailField(unique=True)
>
>
>
> On Wednesday, 8 April 2015 04:02:50 UTC+1, victor menezes wrote:
>>
>> Would it be a bad approach to use a ManyToMany with properties null/blank
>> False?
>>
>> class Email(models.Model):
>> email = models.EmailField(unique=True)
>> def __unicode__(self):
>> return self.email
>>
>> class Person(models.Model):
>> first_name = models.CharField(max_length=100)
>> last_name = models.CharField(max_length=100)
>> emails = models.ManyToManyField(Email, null=False, blank=False)
>> def __unicode__(self):
>> return self.last_name + ', ' + self.first_name
>>
>>
>> On Tuesday, April 7, 2015 at 6:48:22 PM UTC-4, victor menezes wrote:
>>>
>>> Thanks for the help, I end up doing it was easy to implement the email
>>> as TabularInline inside the Person form in the Admin but how would you make
>>> mandatory to have at least one e-mail?
>>> Should I validate inside the save() method of Person class?
>>>
>>>
>>> On Tuesday, April 7, 2015 at 3:55:26 PM UTC-4, Javier Guerra wrote:
>>>>
>>>> On Tue, Apr 7, 2015 at 2:20 PM, victor menezes <menezes...@gmail.com>
>>>> wrote:
>>>> > What would be the best way to make a model with two e-mail fields
>>>> uniques? I
>>>> > was thinking about writing some validation in the save() method but
>>>> would
>>>> > like to know whether Django has some built-in way to deal with it.
>>>>
>>>>
>>>> it's a very bad idea to have plurality by adding a number of similar
>>>> fields. instead, you should have a related table
>>>>
>>>> class Person(models.Model):
>>>> first_name = models.CharField(max_length=100)
>>>> last_name = models.CharField(max_length=100)
>>>>
>>>> class Email(models.Model):
>>>> person = models.ForeignKey(Person)
>>>> email = models.EmailField(unique=True)
>>>>
>>>>
>>>> --
>>>> Javier
>>>>
>>>
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