SyntaxFix

[django] How to define two fields "unique" as couple

Django 2.2+

Using the constraints features UniqueConstraint is preferred over unique_together.

From the Django documentation for unique_together:

Use UniqueConstraint with the constraints option instead.
UniqueConstraint provides more functionality than unique_together.
unique_together may be deprecated in the future.

For example:

class Volume(models.Model):
    id = models.AutoField(primary_key=True)
    journal_id = models.ForeignKey(Journals, db_column='jid', null=True, verbose_name="Journal")
    volume_number = models.CharField('Volume Number', max_length=100)
    comments = models.TextField('Comments', max_length=4000, blank=True)

    class Meta:
        constraints = [
            models.UniqueConstraint(fields=['journal_id', 'volume_number'], name='name of constraint')
        ]

Examples related to django

• How to fix error "ERROR: Command errored out with exit status 1: python." when trying to install django-heroku using pip • Pylint "unresolved import" error in Visual Studio Code • Is it better to use path() or url() in urls.py for django 2.0? • Unable to import path from django.urls • Error loading MySQLdb Module 'Did you install mysqlclient or MySQL-python?' • ImportError: Couldn't import Django • Django - Reverse for '' not found. '' is not a valid view function or pattern name • Class has no objects member • Getting TypeError: __init__() missing 1 required positional argument: 'on_delete' when trying to add parent table after child table with entries • How to switch Python versions in Terminal?

Examples related to django-models

• Getting TypeError: __init__() missing 1 required positional argument: 'on_delete' when trying to add parent table after child table with entries • "Post Image data using POSTMAN" • What does on_delete do on Django models? • Django values_list vs values • What's the difference between select_related and prefetch_related in Django ORM? • Django Model() vs Model.objects.create() • 'NOT NULL constraint failed' after adding to models.py • django - get() returned more than one topic • How to convert Django Model object to dict with its fields and values? • How do I make an auto increment integer field in Django?