Python django.db.migrations.AddField() Examples

def get_migrations_for_django_21_and_newer():
    return [
        # remove primary key information from 'key' field
        migrations.AlterField(
            model_name='resetpasswordtoken',
            name='key',
            field=models.CharField(db_index=True, primary_key=False, max_length=64, unique=True, verbose_name='Key'),
        ),
        # add a new id field
        migrations.AddField(
            model_name='resetpasswordtoken',
            name='id',
            field=models.AutoField(primary_key=True, serialize=False),
            preserve_default=False,
        ),
        migrations.RunPython(
            populate_auto_incrementing_pk_field,
            migrations.RunPython.noop
        ),
    ] 

def test_create_model_add_field_not_through_m2m_through(self):
        """
        AddField should NOT optimize into CreateModel if it's an M2M using a
        through that's created between them.
        """
        # Note: The middle model is not actually a valid through model,
        # but that doesn't matter, as we never render it.
        self.assertDoesNotOptimize(
            [
                migrations.CreateModel("Foo", [("name", models.CharField(max_length=255))]),
                migrations.CreateModel("LinkThrough", []),
                migrations.AddField(
                    "Foo", "link", models.ManyToManyField("migrations.Link", through="migrations.LinkThrough")
                ),
            ],
        ) 

def test_optimize_through_fields(self):
        """
        field-level through checking is working. This should manage to collapse
        model Foo to nonexistence, and model Bar to a single IntegerField
        called "width".
        """
        self.assertOptimizesTo(
            [
                migrations.CreateModel("Foo", [("name", models.CharField(max_length=255))]),
                migrations.CreateModel("Bar", [("size", models.IntegerField())]),
                migrations.AddField("Foo", "age", models.IntegerField()),
                migrations.AddField("Bar", "width", models.IntegerField()),
                migrations.AlterField("Foo", "age", models.IntegerField()),
                migrations.RenameField("Bar", "size", "dimensions"),
                migrations.RemoveField("Foo", "age"),
                migrations.RenameModel("Foo", "Phou"),
                migrations.RemoveField("Bar", "dimensions"),
                migrations.RenameModel("Phou", "Fou"),
                migrations.DeleteModel("Fou"),
            ],
            [
                migrations.CreateModel("Bar", [("width", models.IntegerField())]),
            ],
        ) 

def test_sorted_imports(self):
        """
        #24155 - Tests ordering of imports.
        """
        migration = type(str("Migration"), (migrations.Migration,), {
            "operations": [
                migrations.AddField("mymodel", "myfield", models.DateTimeField(
                    default=datetime.datetime(2012, 1, 1, 1, 1, tzinfo=utc),
                )),
            ]
        })
        writer = MigrationWriter(migration)
        output = writer.as_string()
        self.assertIn(
            "import datetime\n"
            "from django.db import migrations, models\n"
            "from django.utils.timezone import utc\n",
            output
        ) 

def test_column_name_quoting(self):
        """
        Column names that are SQL keywords shouldn't cause problems when used
        in migrations (#22168).
        """
        project_state = self.set_up_test_model("test_regr22168")
        operation = migrations.AddField(
            "Pony",
            "order",
            models.IntegerField(default=0),
        )
        new_state = project_state.clone()
        operation.state_forwards("test_regr22168", new_state)
        with connection.schema_editor() as editor:
            operation.database_forwards("test_regr22168", editor, project_state, new_state)
        self.assertColumnExists("test_regr22168_pony", "order") 

def test_repoint_field_m2m(self):
        project_state = self.set_up_test_model("test_alflmm", second_model=True, third_model=True)

        project_state = self.apply_operations("test_alflmm", project_state, operations=[
            migrations.AddField("Pony", "places", models.ManyToManyField("Stable", related_name="ponies"))
        ])
        Pony = project_state.apps.get_model("test_alflmm", "Pony")

        project_state = self.apply_operations("test_alflmm", project_state, operations=[
            migrations.AlterField("Pony", "places", models.ManyToManyField(to="Van", related_name="ponies"))
        ])

        # Ensure the new field actually works
        Pony = project_state.apps.get_model("test_alflmm", "Pony")
        p = Pony.objects.create(pink=False, weight=4.55)
        p.places.create()
        self.assertEqual(p.places.count(), 1)
        p.places.all().delete() 

def test_remove_field_m2m(self):
        project_state = self.set_up_test_model("test_rmflmm", second_model=True)

        project_state = self.apply_operations("test_rmflmm", project_state, operations=[
            migrations.AddField("Pony", "stables", models.ManyToManyField("Stable", related_name="ponies"))
        ])
        self.assertTableExists("test_rmflmm_pony_stables")

        with_field_state = project_state.clone()
        operations = [migrations.RemoveField("Pony", "stables")]
        project_state = self.apply_operations("test_rmflmm", project_state, operations=operations)
        self.assertTableNotExists("test_rmflmm_pony_stables")

        # And test reversal
        self.unapply_operations("test_rmflmm", with_field_state, operations=operations)
        self.assertTableExists("test_rmflmm_pony_stables") 

def test_remove_field_m2m_with_through(self):
        project_state = self.set_up_test_model("test_rmflmmwt", second_model=True)

        self.assertTableNotExists("test_rmflmmwt_ponystables")
        project_state = self.apply_operations("test_rmflmmwt", project_state, operations=[
            migrations.CreateModel("PonyStables", fields=[
                ("pony", models.ForeignKey('test_rmflmmwt.Pony', models.CASCADE)),
                ("stable", models.ForeignKey('test_rmflmmwt.Stable', models.CASCADE)),
            ]),
            migrations.AddField(
                "Pony", "stables",
                models.ManyToManyField("Stable", related_name="ponies", through='test_rmflmmwt.PonyStables')
            )
        ])
        self.assertTableExists("test_rmflmmwt_ponystables")

        operations = [migrations.RemoveField("Pony", "stables"), migrations.DeleteModel("PonyStables")]
        self.apply_operations("test_rmflmmwt", project_state, operations=operations) 

def test_create_model_add_field_not_through_m2m_through(self):
        """
        AddField should NOT optimize into CreateModel if it's an M2M using a
        through that's created between them.
        """
        # Note: The middle model is not actually a valid through model,
        # but that doesn't matter, as we never render it.
        self.assertDoesNotOptimize(
            [
                migrations.CreateModel("Foo", [("name", models.CharField(max_length=255))]),
                migrations.CreateModel("LinkThrough", []),
                migrations.AddField(
                    "Foo", "link", models.ManyToManyField("migrations.Link", through="migrations.LinkThrough")
                ),
            ],
        ) 

def test_optimize_through_fields(self):
        """
        field-level through checking is working. This should manage to collapse
        model Foo to nonexistence, and model Bar to a single IntegerField
        called "width".
        """
        self.assertOptimizesTo(
            [
                migrations.CreateModel("Foo", [("name", models.CharField(max_length=255))]),
                migrations.CreateModel("Bar", [("size", models.IntegerField())]),
                migrations.AddField("Foo", "age", models.IntegerField()),
                migrations.AddField("Bar", "width", models.IntegerField()),
                migrations.AlterField("Foo", "age", models.IntegerField()),
                migrations.RenameField("Bar", "size", "dimensions"),
                migrations.RemoveField("Foo", "age"),
                migrations.RenameModel("Foo", "Phou"),
                migrations.RemoveField("Bar", "dimensions"),
                migrations.RenameModel("Phou", "Fou"),
                migrations.DeleteModel("Fou"),
            ],
            [
                migrations.CreateModel("Bar", [("width", models.IntegerField())]),
            ],
        ) 

def test_sorted_imports(self):
        """
        #24155 - Tests ordering of imports.
        """
        migration = type("Migration", (migrations.Migration,), {
            "operations": [
                migrations.AddField("mymodel", "myfield", models.DateTimeField(
                    default=datetime.datetime(2012, 1, 1, 1, 1, tzinfo=utc),
                )),
            ]
        })
        writer = MigrationWriter(migration)
        output = writer.as_string()
        self.assertIn(
            "import datetime\n"
            "from django.db import migrations, models\n"
            "from django.utils.timezone import utc\n",
            output
        ) 

def test_column_name_quoting(self):
        """
        Column names that are SQL keywords shouldn't cause problems when used
        in migrations (#22168).
        """
        project_state = self.set_up_test_model("test_regr22168")
        operation = migrations.AddField(
            "Pony",
            "order",
            models.IntegerField(default=0),
        )
        new_state = project_state.clone()
        operation.state_forwards("test_regr22168", new_state)
        with connection.schema_editor() as editor:
            operation.database_forwards("test_regr22168", editor, project_state, new_state)
        self.assertColumnExists("test_regr22168_pony", "order") 

def test_repoint_field_m2m(self):
        project_state = self.set_up_test_model("test_alflmm", second_model=True, third_model=True)

        project_state = self.apply_operations("test_alflmm", project_state, operations=[
            migrations.AddField("Pony", "places", models.ManyToManyField("Stable", related_name="ponies"))
        ])
        Pony = project_state.apps.get_model("test_alflmm", "Pony")

        project_state = self.apply_operations("test_alflmm", project_state, operations=[
            migrations.AlterField("Pony", "places", models.ManyToManyField(to="Van", related_name="ponies"))
        ])

        # Ensure the new field actually works
        Pony = project_state.apps.get_model("test_alflmm", "Pony")
        p = Pony.objects.create(pink=False, weight=4.55)
        p.places.create()
        self.assertEqual(p.places.count(), 1)
        p.places.all().delete() 

def test_remove_field_m2m(self):
        project_state = self.set_up_test_model("test_rmflmm", second_model=True)

        project_state = self.apply_operations("test_rmflmm", project_state, operations=[
            migrations.AddField("Pony", "stables", models.ManyToManyField("Stable", related_name="ponies"))
        ])
        self.assertTableExists("test_rmflmm_pony_stables")

        with_field_state = project_state.clone()
        operations = [migrations.RemoveField("Pony", "stables")]
        project_state = self.apply_operations("test_rmflmm", project_state, operations=operations)
        self.assertTableNotExists("test_rmflmm_pony_stables")

        # And test reversal
        self.unapply_operations("test_rmflmm", with_field_state, operations=operations)
        self.assertTableExists("test_rmflmm_pony_stables") 

def test_remove_field_m2m_with_through(self):
        project_state = self.set_up_test_model("test_rmflmmwt", second_model=True)

        self.assertTableNotExists("test_rmflmmwt_ponystables")
        project_state = self.apply_operations("test_rmflmmwt", project_state, operations=[
            migrations.CreateModel("PonyStables", fields=[
                ("pony", models.ForeignKey('test_rmflmmwt.Pony', models.CASCADE)),
                ("stable", models.ForeignKey('test_rmflmmwt.Stable', models.CASCADE)),
            ]),
            migrations.AddField(
                "Pony", "stables",
                models.ManyToManyField("Stable", related_name="ponies", through='test_rmflmmwt.PonyStables')
            )
        ])
        self.assertTableExists("test_rmflmmwt_ponystables")

        operations = [migrations.RemoveField("Pony", "stables"), migrations.DeleteModel("PonyStables")]
        self.apply_operations("test_rmflmmwt", project_state, operations=operations) 

def test_create_model_reordering(self):
        """
        AddField optimizes into CreateModel if it's a FK to a model that's
        between them (and there's no FK in the other direction), by changing
        the order of the CreateModel operations.
        """
        self.assertOptimizesTo(
            [
                migrations.CreateModel('Foo', [('name', models.CharField(max_length=255))]),
                migrations.CreateModel('Link', [('url', models.TextField())]),
                migrations.AddField('Foo', 'link', models.ForeignKey('migrations.Link', models.CASCADE)),
            ],
            [
                migrations.CreateModel('Link', [('url', models.TextField())]),
                migrations.CreateModel('Foo', [
                    ('name', models.CharField(max_length=255)),
                    ('link', models.ForeignKey('migrations.Link', models.CASCADE))
                ]),
            ],
        ) 

def test_create_model_reordering_circular_fk(self):
        """
        CreateModel reordering behavior doesn't result in an infinite loop if
        there are FKs in both directions.
        """
        self.assertOptimizesTo(
            [
                migrations.CreateModel('Bar', [('url', models.TextField())]),
                migrations.CreateModel('Foo', [('name', models.CharField(max_length=255))]),
                migrations.AddField('Bar', 'foo_fk', models.ForeignKey('migrations.Foo', models.CASCADE)),
                migrations.AddField('Foo', 'bar_fk', models.ForeignKey('migrations.Bar', models.CASCADE)),
            ],
            [
                migrations.CreateModel('Foo', [('name', models.CharField(max_length=255))]),
                migrations.CreateModel('Bar', [
                    ('url', models.TextField()),
                    ('foo_fk', models.ForeignKey('migrations.Foo', models.CASCADE)),
                ]),
                migrations.AddField('Foo', 'bar_fk', models.ForeignKey('migrations.Foo', models.CASCADE)),
            ],
        ) 

def test_create_model_add_field_not_through_m2m_through(self):
        """
        AddField should NOT optimize into CreateModel if it's an M2M using a
        through that's created between them.
        """
        self.assertDoesNotOptimize(
            [
                migrations.CreateModel('Employee', []),
                migrations.CreateModel('Employer', []),
                migrations.CreateModel('Employment', [
                    ('employee', models.ForeignKey('migrations.Employee', models.CASCADE)),
                    ('employment', models.ForeignKey('migrations.Employer', models.CASCADE)),
                ]),
                migrations.AddField(
                    'Employer', 'employees', models.ManyToManyField(
                        'migrations.Employee', through='migrations.Employment',
                    )
                ),
            ],
        ) 

def test_optimize_through_fields(self):
        """
        field-level through checking is working. This should manage to collapse
        model Foo to nonexistence, and model Bar to a single IntegerField
        called "width".
        """
        self.assertOptimizesTo(
            [
                migrations.CreateModel("Foo", [("name", models.CharField(max_length=255))]),
                migrations.CreateModel("Bar", [("size", models.IntegerField())]),
                migrations.AddField("Foo", "age", models.IntegerField()),
                migrations.AddField("Bar", "width", models.IntegerField()),
                migrations.AlterField("Foo", "age", models.IntegerField()),
                migrations.RenameField("Bar", "size", "dimensions"),
                migrations.RemoveField("Foo", "age"),
                migrations.RenameModel("Foo", "Phou"),
                migrations.RemoveField("Bar", "dimensions"),
                migrations.RenameModel("Phou", "Fou"),
                migrations.DeleteModel("Fou"),
            ],
            [
                migrations.CreateModel("Bar", [("width", models.IntegerField())]),
            ],
        ) 

def test_sorted_imports(self):
        """
        #24155 - Tests ordering of imports.
        """
        migration = type("Migration", (migrations.Migration,), {
            "operations": [
                migrations.AddField("mymodel", "myfield", models.DateTimeField(
                    default=datetime.datetime(2012, 1, 1, 1, 1, tzinfo=utc),
                )),
            ]
        })
        writer = MigrationWriter(migration)
        output = writer.as_string()
        self.assertIn(
            "import datetime\n"
            "from django.db import migrations, models\n"
            "from django.utils.timezone import utc\n",
            output
        ) 

def test_column_name_quoting(self):
        """
        Column names that are SQL keywords shouldn't cause problems when used
        in migrations (#22168).
        """
        project_state = self.set_up_test_model("test_regr22168")
        operation = migrations.AddField(
            "Pony",
            "order",
            models.IntegerField(default=0),
        )
        new_state = project_state.clone()
        operation.state_forwards("test_regr22168", new_state)
        with connection.schema_editor() as editor:
            operation.database_forwards("test_regr22168", editor, project_state, new_state)
        self.assertColumnExists("test_regr22168_pony", "order") 

def test_alter_field_m2m(self):
        project_state = self.set_up_test_model("test_alflmm", second_model=True)

        project_state = self.apply_operations("test_alflmm", project_state, operations=[
            migrations.AddField("Pony", "stables", models.ManyToManyField("Stable", related_name="ponies"))
        ])
        Pony = project_state.apps.get_model("test_alflmm", "Pony")
        self.assertFalse(Pony._meta.get_field('stables').blank)

        project_state = self.apply_operations("test_alflmm", project_state, operations=[
            migrations.AlterField(
                "Pony", "stables", models.ManyToManyField(to="Stable", related_name="ponies", blank=True)
            )
        ])
        Pony = project_state.apps.get_model("test_alflmm", "Pony")
        self.assertTrue(Pony._meta.get_field('stables').blank) 

def test_repoint_field_m2m(self):
        project_state = self.set_up_test_model("test_alflmm", second_model=True, third_model=True)

        project_state = self.apply_operations("test_alflmm", project_state, operations=[
            migrations.AddField("Pony", "places", models.ManyToManyField("Stable", related_name="ponies"))
        ])
        Pony = project_state.apps.get_model("test_alflmm", "Pony")

        project_state = self.apply_operations("test_alflmm", project_state, operations=[
            migrations.AlterField("Pony", "places", models.ManyToManyField(to="Van", related_name="ponies"))
        ])

        # Ensure the new field actually works
        Pony = project_state.apps.get_model("test_alflmm", "Pony")
        p = Pony.objects.create(pink=False, weight=4.55)
        p.places.create()
        self.assertEqual(p.places.count(), 1)
        p.places.all().delete() 

def test_remove_field_m2m(self):
        project_state = self.set_up_test_model("test_rmflmm", second_model=True)

        project_state = self.apply_operations("test_rmflmm", project_state, operations=[
            migrations.AddField("Pony", "stables", models.ManyToManyField("Stable", related_name="ponies"))
        ])
        self.assertTableExists("test_rmflmm_pony_stables")

        with_field_state = project_state.clone()
        operations = [migrations.RemoveField("Pony", "stables")]
        project_state = self.apply_operations("test_rmflmm", project_state, operations=operations)
        self.assertTableNotExists("test_rmflmm_pony_stables")

        # And test reversal
        self.unapply_operations("test_rmflmm", with_field_state, operations=operations)
        self.assertTableExists("test_rmflmm_pony_stables") 

def test_remove_field_m2m_with_through(self):
        project_state = self.set_up_test_model("test_rmflmmwt", second_model=True)

        self.assertTableNotExists("test_rmflmmwt_ponystables")
        project_state = self.apply_operations("test_rmflmmwt", project_state, operations=[
            migrations.CreateModel("PonyStables", fields=[
                ("pony", models.ForeignKey('test_rmflmmwt.Pony', models.CASCADE)),
                ("stable", models.ForeignKey('test_rmflmmwt.Stable', models.CASCADE)),
            ]),
            migrations.AddField(
                "Pony", "stables",
                models.ManyToManyField("Stable", related_name="ponies", through='test_rmflmmwt.PonyStables')
            )
        ])
        self.assertTableExists("test_rmflmmwt_ponystables")

        operations = [migrations.RemoveField("Pony", "stables"), migrations.DeleteModel("PonyStables")]
        self.apply_operations("test_rmflmmwt", project_state, operations=operations) 

def test_add_field_ignore_swapped(self):
        """
        Tests the AddField operation.
        """
        # Test the state alteration
        operation = migrations.AddField(
            "Pony",
            "height",
            models.FloatField(null=True, default=5),
        )
        project_state, new_state = self.make_test_state("test_adfligsw", operation)
        # Test the database alteration
        self.assertTableNotExists("test_adfligsw_pony")
        with connection.schema_editor() as editor:
            operation.database_forwards("test_adfligsw", editor, project_state, new_state)
        self.assertTableNotExists("test_adfligsw_pony")
        # And test reversal
        with connection.schema_editor() as editor:
            operation.database_backwards("test_adfligsw", editor, new_state, project_state)
        self.assertTableNotExists("test_adfligsw_pony") 

def add_field(field, filters: List[str]):
    """Adds the specified field to a model.

    Arguments:
        field:
            The field to add to a model.

        filters:
            List of strings to filter
            SQL statements on.
    """

    model = define_fake_model()
    state = migrations.state.ProjectState.from_apps(apps)

    apply_migration([migrations.CreateModel(model.__name__, fields=[])], state)

    with filtered_schema_editor(*filters) as calls:
        apply_migration(
            [migrations.AddField(model.__name__, "title", field)], state
        )

    yield calls 

def reduce_add_field_alter_field(self, operation, other, in_between):
        if (operation.model_name_lower == other.model_name_lower and
                operation.name_lower == other.name_lower):
            return [
                migrations.AddField(
                    model_name=operation.model_name,
                    name=operation.name,
                    field=other.field,
                )
            ] 

def reduce_add_field_rename_field(self, operation, other, in_between):
        if (operation.model_name_lower == other.model_name_lower and
                operation.name_lower == other.old_name_lower):
            return [
                migrations.AddField(
                    model_name=operation.model_name,
                    name=other.new_name,
                    field=operation.field,
                )
            ] 

def get_migrations_for_django_before_21():
    return [
        # add a new id field (without primary key information)
        migrations.AddField(
            model_name='resetpasswordtoken',
            name='id',
            field=models.IntegerField(null=True),
            preserve_default=True,
        ),
        # fill the new pk field
        migrations.RunPython(
            populate_auto_incrementing_pk_field,
            migrations.RunPython.noop
        ),
        # add primary key information to id field
        migrations.AlterField(
            model_name='resetpasswordtoken',
            name='id',
            field=models.AutoField(primary_key=True, serialize=False)
        ),
        # remove primary key information from 'key' field
        migrations.AlterField(
            model_name='resetpasswordtoken',
            name='key',
            field=models.CharField(db_index=True, max_length=64, unique=True, verbose_name='Key'),
        ),
    ]