Update serialization examples from unique_together to UniqueConstraint

[Willem Van Onsem]

The idea is thus to transform code on the page like:

class Mymodel(model):
      class Meta:
           unique_together = [[ 'field1', 'field2' ]]

to:

class Mymodel(model):
      class Meta:
           constraints = [models.UniqueConstraint(fields=('field1', 'field2'), name='field1_2_unique')]

[Mariusz Felisiak]

​PR

[Waqar Ali]

I believe you're confusing model meta option constratins with unique_together. UniqueConstraint is a DB constraint assigned to constraints option in Meta whereas unique together is another option on Meta level.

class Mymodel(model):
      class Meta:
           unique_together = [ 'field1', 'field2' ]
           constratints = [ UniqueConstraint ]

[Willem Van Onsem]

Replying to Waqar ALi:
No, Django had in the early days unique_together, now it still has, but as the note on the documentation says (​https://docs.djangoproject.com/en/4.1/ref/models/options/#django.db.models.Options.unique_together):

Use UniqueConstraint with the constraints option instead.

It "translated" to a unique constraint. But it was less flexible since one could not give it a custom name, add a condition, make it a functional unique constraint, etc. So UniqueConstraint is the "new way" to define this, whereas unique_together is the "old" way to generate such database constraint.

[Willem Van Onsem]

The idea is thus to transform code on the page like:

class Mymodel(model):
      class Meta:
           unique_together = [[ 'field1', 'field2' ]]

to:

class Mymodel(model):
      class Meta:
           constraints = [models.UniqueConstraint(fields=('field1', 'field2'), name='field1_2_unique')]

[Mariusz Felisiak <felisiak.mariusz@…>]

In 292aaca:

Fixed #34311 -- Updated serialization docs from unique_together to UniqueConstraint.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 7a88b1f:

[4.2.x] Fixed #34311 -- Updated serialization docs from unique_together to UniqueConstraint.

Backport of 292aacaf6c3d6956ca2c51c41e36dbf425389346 from main