to IntegrityError on save(), ValidationError is also raised during model validation when the UniqueConstraint is violated. CheckConstraint class CheckConstraint(*, check, name) Creates a check constraint name The name of the constraint. UniqueConstraint class UniqueConstraint(*, fields, name, condition=None) Creates a unique constraint in the database. fields UniqueConstraint.fields A list of field names that constraint to enforce. For example, UniqueConstraint(fields=['room', 'date'], name='unique_booking') ensures each room can only be booked once for each date. name UniqueConstraint.name The name of the constraint

CharField(max_length=100) birthdate = models.DateField() class Meta: constraints = [ models.UniqueConstraint( fields=["first_name", "last_name"], name="uniq DateField() objects = PersonManager() class Meta: constraints = [ models.UniqueConstraint( fields=[first_name], "last_name"], name="uniqu mean that your model will have a uniqueness clause (either unique=True on a single field, or a UniqueConstraint or unique_together over multiple fields) for the field or fields in your natural key. However

CharField(max_length=100) birthdate = models.DateField() class Meta: constraints = [ models.UniqueConstraint( fields=[first_name, "last_name"], name="unique_first_last_name" DateField() objects = PersonManager() class Meta: constraints = [ models.UniqueConstraint( fields=[first_name,"last_name"], name="unique_ Whatever fields you use for a natural key must be able to uniquely identify an object. This UniqueConstraint or unique_together over multiple fields) for the field or fields in your natural key. However

CharField(max_length=100) birthdate = models.DateField() class Meta: constraints = [ models.UniqueConstraint( fields=["first_name", "last_name"], name="uniq DateField() objects = PersonManager() class Meta: constraints = [ models.UniqueConstraint( fields=[first_name], "last_name"], name="uniqu mean that your model will have a uniqueness clause (either unique=True on a single field, or a UniqueConstraint or unique_together over multiple fields) for the field or fields in your natural key. However

birthdate = models.DateField() class Meta: constraints = [ models.UniqueConstraint( fields=["first_name", "last_name"], name="unique_first_last_name" objects = PersonManager() class Meta: constraints = [ models.UniqueConstraint( fields=["first_name", "last_name"], name="unique_first_last_name" mean that your model will have a uniqueness clause (either unique=True on a single field, or a UniqueConstraint or unique_together over multiple fields) for the field or fields in your natural key. However

CharField(max_length=100) birthdate = models.DateField() class Meta: constraints = [ models.UniqueConstraint( fields=["first_name", "last_name"], name="uniq DateField() objects = PersonManager() class Meta: constraints = [ models.UniqueConstraint( fields=[first_name], "last_name"], name="uniqu mean that your model will have a uniqueness clause (either unique=True on a single field, or a UniqueConstraint or unique_together over multiple fields) for the field or fields in your natural key. However

CharField(max_length=100) birthdate = models.DateField() class Meta: constraints = [ models.UniqueConstraint( fields=["first_name", "last_name"], name="uniq mean that your model will have a uniqueness clause (either unique=True on a single field, or a UniqueConstraint or unique_together over multiple fields) for the field or fields in your natural key. However DateField() objects = PersonManager() class Meta: constraints = [ models.UniqueConstraint( fields=["first_name", "last_name"], name=&

name_idx', ) creates an index on Lower('username') using varchar_pattern_ops. UniqueConstraint( OpClass(Upper('description'), name='text_pattern_ops'), name=' relationship. Note: If you don’t want multiple associations between the same instances, add a UniqueConstraint including the from and to fields. Django’s automatically generated many-to-many tables include Q(age__isnull=True), name='age_gte_18') The violation error message argument was added. UniqueConstraint class UniqueConstraint(*expressions, fields=(), name=None, condition=None, deferrable=None, include=None

creates an index on Lower('username') using varchar_pattern_ops. Another example: UniqueConstraint( OpClass(Upper('description'), name='text_pattern_ops'), name=' relationship. Note: If you don’t want multiple associations between the same instances, add a UniqueConstraint including the from and to fields. Django’s automatically generated many-to-many tables include to IntegrityError on save(), ValidationError is also raised during model validation when the UniqueConstraint is violated. CheckConstraint class CheckConstraint(*, check, name) Creates a check constraint

relationship. Note If you don’t want multiple associations between the same instances, add a UniqueConstraint including the from and to fields. Django’s automatically generated many-to-many tables include to IntegrityError on save(), ValidationError is also raised during model validation when the UniqueConstraint is violated. CheckConstraint class CheckConstraint(*, check, name) Creates a check constraint constraint. UniqueConstraint class UniqueConstraint(*, fields, name, condition=None, deferrable=None, include=None, opclasses=()) Creates a unique constraint in the database. fields UniqueConstraint.fields