Commit 27b6f284 authored by Andrew Godwin's avatar Andrew Godwin
Browse files

Fixed #23264: Schema backends honour db_constraint

parent 8fe40686

django/db/backends/schema.py

+6 −4
Original line number Diff line number Diff line
@@ -228,7 +228,7 @@ class BaseDatabaseSchemaEditor(object): 
                    }

                )

            # FK

            if field.rel:

            if field.rel and field.db_constraint:

                to_table = field.rel.to._meta.db_table

                to_column = field.rel.to._meta.get_field(field.rel.field_name).column

                if self.connection.features.supports_foreign_keys:
@@ -430,7 +430,7 @@ class BaseDatabaseSchemaEditor(object): 
                }

            )

        # Add any FK constraints later

        if field.rel and self.connection.features.supports_foreign_keys:

        if field.rel and self.connection.features.supports_foreign_keys and field.db_constraint:

            to_table = field.rel.to._meta.db_table

            to_column = field.rel.to._meta.get_field(field.rel.field_name).column

            self.deferred_sql.append(
@@ -530,7 +530,7 @@ class BaseDatabaseSchemaEditor(object): 
                )

        # Drop any FK constraints, we'll remake them later

        fks_dropped = set()

        if old_field.rel:

        if old_field.rel and old_field.db_constraint:

            fk_names = self._constraint_names(model, [old_field.column], foreign_key=True)

            if strict and len(fk_names) != 1:

                raise ValueError("Found wrong number (%s) of foreign key constraints for %s.%s" % (
@@ -739,7 +739,9 @@ class BaseDatabaseSchemaEditor(object): 
                }

            )

        # Does it have a foreign key?

        if new_field.rel and fks_dropped:

        if new_field.rel and \

           (fks_dropped or (old_field.rel and not old_field.db_constraint)) and \

           new_field.db_constraint:

            to_table = new_field.rel.to._meta.db_table

            to_column = new_field.rel.get_related_field().column

            self.execute(

tests/schema/models.py

+9 −0
Original line number Diff line number Diff line
@@ -50,6 +50,15 @@ class Book(models.Model): 
        apps = new_apps





class BookWeak(models.Model):

    author = models.ForeignKey(Author, db_constraint=False)

    title = models.CharField(max_length=100, db_index=True)

    pub_date = models.DateTimeField()



    class Meta:

        apps = new_apps





class BookWithM2M(models.Model):

    author = models.ForeignKey(Author)

    title = models.CharField(max_length=100, db_index=True)

tests/schema/tests.py

+91 −2
Original line number Diff line number Diff line
@@ -10,7 +10,7 @@ from django.db.transaction import atomic 
from .models import (Author, AuthorWithM2M, Book, BookWithLongName,

    BookWithSlug, BookWithM2M, Tag, TagIndexed, TagM2MTest, TagUniqueRename,

    UniqueTest, Thing, TagThrough, BookWithM2MThrough, AuthorTag, AuthorWithM2MThrough,

    AuthorWithEvenLongerName)

    AuthorWithEvenLongerName, BookWeak)





class SchemaTests(TransactionTestCase):
@@ -27,7 +27,8 @@ class SchemaTests(TransactionTestCase): 
    models = [

        Author, AuthorWithM2M, Book, BookWithLongName, BookWithSlug,

        BookWithM2M, Tag, TagIndexed, TagM2MTest, TagUniqueRename, UniqueTest,

        Thing, TagThrough, BookWithM2MThrough, AuthorWithEvenLongerName

        Thing, TagThrough, BookWithM2MThrough, AuthorWithEvenLongerName,

        BookWeak,

    ]



    # Utility functions
@@ -150,6 +151,94 @@ class SchemaTests(TransactionTestCase): 
        else:

            self.fail("No FK constraint for author_id found")



    @unittest.skipUnless(connection.features.supports_foreign_keys, "No FK support")

    def test_fk_db_constraint(self):

        "Tests that the db_constraint parameter is respected"

        # Create the table

        with connection.schema_editor() as editor:

            editor.create_model(Tag)

            editor.create_model(Author)

            editor.create_model(BookWeak)

        # Check that initial tables are there

        list(Author.objects.all())

        list(Tag.objects.all())

        list(BookWeak.objects.all())

        # Check that BookWeak doesn't have an FK constraint

        constraints = self.get_constraints(BookWeak._meta.db_table)

        for name, details in constraints.items():

            if details['columns'] == ["author_id"] and details['foreign_key']:

                self.fail("FK constraint for author_id found")

        # Make a db_constraint=False FK

        new_field = ForeignKey(Tag, db_constraint=False)

        new_field.set_attributes_from_name("tag")

        with connection.schema_editor() as editor:

            editor.add_field(

                Author,

                new_field,

            )

        # Make sure no FK constraint is present

        constraints = self.get_constraints(Author._meta.db_table)

        for name, details in constraints.items():

            if details['columns'] == ["tag_id"] and details['foreign_key']:

                self.fail("FK constraint for tag_id found")

        # Alter to one with a constraint

        new_field_2 = ForeignKey(Tag)

        new_field_2.set_attributes_from_name("tag")

        with connection.schema_editor() as editor:

            editor.alter_field(

                Author,

                new_field,

                new_field_2,

                strict=True,

            )

        # Make sure the new FK constraint is present

        constraints = self.get_constraints(Author._meta.db_table)

        for name, details in constraints.items():

            if details['columns'] == ["tag_id"] and details['foreign_key']:

                self.assertEqual(details['foreign_key'], ('schema_tag', 'id'))

                break

        else:

            self.fail("No FK constraint for tag_id found")

        # Alter to one without a constraint again

        new_field_2 = ForeignKey(Tag)

        new_field_2.set_attributes_from_name("tag")

        with connection.schema_editor() as editor:

            editor.alter_field(

                Author,

                new_field_2,

                new_field,

                strict=True,

            )

        # Make sure no FK constraint is present

        constraints = self.get_constraints(Author._meta.db_table)

        for name, details in constraints.items():

            if details['columns'] == ["tag_id"] and details['foreign_key']:

                self.fail("FK constraint for tag_id found")



    @unittest.skipUnless(connection.features.supports_foreign_keys, "No FK support")

    def test_m2m_db_constraint(self):

        # Create the table

        with connection.schema_editor() as editor:

            editor.create_model(Tag)

            editor.create_model(Author)

        # Check that initial tables are there

        list(Author.objects.all())

        list(Tag.objects.all())

        # Make a db_constraint=False FK

        new_field = ManyToManyField("schema.Tag", related_name="authors", db_constraint=False)

        new_field.contribute_to_class(Author, "tags")

        # Add the field

        with connection.schema_editor() as editor:

            editor.add_field(

                Author,

                new_field,

            )

        # Make sure no FK constraint is present

        constraints = self.get_constraints(new_field.rel.through._meta.db_table)

        for name, details in constraints.items():

            if details['columns'] == ["tag_id"] and details['foreign_key']:

                self.fail("FK constraint for tag_id found")



    def test_add_field(self):

        """

        Tests adding fields to models