field of tuples

[Jaroslav Dobrek]

Hello,

how can I create a field that contains tuples of entities? An example:
A model "Candidate" (someone who applies for a job) might have a field
"languages" which is a list of tuples consisting of a language and a
proficiency level.

Jaroslav

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Re: field of tuples

[Sam Basl]

Wouldn't it be better to do this sort of thing with a related model?
On Feb 7, 2012 4:44 AM, "Jaroslav Dobrek"  wrote:

> Hello,
>
> how can I create a field that contains tuples of entities? An example:
> A model "Candidate" (someone who applies for a job) might have a field
> "languages" which is a list of tuples consisting of a language and a
> proficiency level.
>
> Jaroslav
>
> --
> You received this message because you are subscribed to the Google Groups
> "Django users" group.
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>
>

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Re: field of tuples

[akaariai]

On Feb 7, 11:44 am, Jaroslav Dobrek  wrote:
> Hello,
>
> how can I create a field that contains tuples of entities? An example:
> A model "Candidate" (someone who applies for a job) might have a field
> "languages" which is a list of tuples consisting of a language and a
> proficiency level.

As others have said: don't. If you ever need to do any DB queries
involving the proficiencies of the candidates (like "how many
candidates we have who are proficient in English") you are screwed.

You will most likely get what you want with:
class CandidateLangProficiency(models.Model):
 candidate = models.ForeignKey(Candidate,
related_name='proficiencies')
 lang = models.CharField(max_length=2, choices=(('fi',
'Finnish'), ...) # Or a foreign key.
 proficiency = models.IntegerField(choices=...)
 class Meta:
 unique_together = ('candidate', 'lang')

If you can use Django 1.4, its prefetch_related will be your friend.

If you really know what you are doing you can write a custom model
field. Django's documentation should contain examples of that.

 - Anssi

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