Annotate query set with field value

Question

Multilanguage website with translations stored in columns of one table. Need to pass query set to template with already filtered translations. Language variable is stored in session.

class Item(models.Model):
    name = models.CharField(max_length=128)
    description = models.ForeignKey(Localization)

class Localization(models.Model):
    klingon = models.TextField(blank=True, null=True, verbose_name='klingon')
    english = models.TextField(blank=True, null=True, verbose_name='english')

Thought would be nice just to annotate the qs with the needed text, however I failed to find how to annotate with a field value. Something like

item = Item.objects.all().annotate(text=description.klingon)

Another approach would be to use a template filter like

item.description|choose_lang:request

but sorting the qs before the template seems neater.

Answer 1

You can use the F() expression here

from django.db.models import F    
item = Item.objects.all().annotate(text=F('description__klingon'))

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