| from django.db import models |
|
|
|
|
| class Product(models.Model): |
| price = models.IntegerField(null=True) |
| discounted_price = models.IntegerField(null=True) |
| unit = models.CharField(max_length=15, null=True) |
|
|
| class Meta: |
| required_db_features = { |
| "supports_table_check_constraints", |
| } |
| constraints = [ |
| models.CheckConstraint( |
| check=models.Q(price__gt=models.F("discounted_price")), |
| name="price_gt_discounted_price", |
| ), |
| models.CheckConstraint( |
| check=models.Q(price__gt=0), |
| name="%(app_label)s_%(class)s_price_gt_0", |
| ), |
| models.CheckConstraint( |
| check=models.Q( |
| models.Q(unit__isnull=True) | models.Q(unit__in=["μg/mL", "ng/mL"]) |
| ), |
| name="unicode_unit_list", |
| ), |
| ] |
|
|
|
|
| class UniqueConstraintProduct(models.Model): |
| name = models.CharField(max_length=255) |
| color = models.CharField(max_length=32, null=True) |
|
|
| class Meta: |
| constraints = [ |
| models.UniqueConstraint( |
| fields=["name", "color"], |
| name="name_color_uniq", |
| |
| violation_error_code="custom_code", |
| violation_error_message="Custom message", |
| ) |
| ] |
|
|
|
|
| class ChildUniqueConstraintProduct(UniqueConstraintProduct): |
| pass |
|
|
|
|
| class UniqueConstraintConditionProduct(models.Model): |
| name = models.CharField(max_length=255) |
| color = models.CharField(max_length=32, null=True) |
|
|
| class Meta: |
| required_db_features = {"supports_partial_indexes"} |
| constraints = [ |
| models.UniqueConstraint( |
| fields=["name"], |
| name="name_without_color_uniq", |
| condition=models.Q(color__isnull=True), |
| ), |
| ] |
|
|
|
|
| class UniqueConstraintDeferrable(models.Model): |
| name = models.CharField(max_length=255) |
| shelf = models.CharField(max_length=31) |
|
|
| class Meta: |
| required_db_features = { |
| "supports_deferrable_unique_constraints", |
| } |
| constraints = [ |
| models.UniqueConstraint( |
| fields=["name"], |
| name="name_init_deferred_uniq", |
| deferrable=models.Deferrable.DEFERRED, |
| ), |
| models.UniqueConstraint( |
| fields=["shelf"], |
| name="sheld_init_immediate_uniq", |
| deferrable=models.Deferrable.IMMEDIATE, |
| ), |
| ] |
|
|
|
|
| class UniqueConstraintInclude(models.Model): |
| name = models.CharField(max_length=255) |
| color = models.CharField(max_length=32, null=True) |
|
|
| class Meta: |
| required_db_features = { |
| "supports_table_check_constraints", |
| "supports_covering_indexes", |
| } |
| constraints = [ |
| models.UniqueConstraint( |
| fields=["name"], |
| name="name_include_color_uniq", |
| include=["color"], |
| ), |
| ] |
|
|
|
|
| class AbstractModel(models.Model): |
| age = models.IntegerField() |
|
|
| class Meta: |
| abstract = True |
| required_db_features = { |
| "supports_table_check_constraints", |
| } |
| constraints = [ |
| models.CheckConstraint( |
| check=models.Q(age__gte=18), |
| name="%(app_label)s_%(class)s_adult", |
| ), |
| ] |
|
|
|
|
| class ChildModel(AbstractModel): |
| pass |
|
|