Python django.db.migrations.state.ProjectState() Examples

def make_state(self, nodes=None, at_end=True, real_apps=None):
        """
        Given a migration node or nodes, returns a complete ProjectState for it.
        If at_end is False, returns the state before the migration has run.
        If nodes is not provided, returns the overall most current project state.
        """
        if nodes is None:
            nodes = list(self.leaf_nodes())
        if len(nodes) == 0:
            return ProjectState()
        if not isinstance(nodes[0], tuple):
            nodes = [nodes]
        plan = []
        for node in nodes:
            for migration in self.forwards_plan(node):
                if migration not in plan:
                    if not at_end and migration in nodes:
                        continue
                    plan.append(migration)
        project_state = ProjectState(real_apps=real_apps)
        for node in plan:
            project_state = self.nodes[node].mutate_state(project_state, preserve=False)
        return project_state 

def _test_create_model(self, app_label, should_run):
        """
        CreateModel honors multi-db settings.
        """
        operation = migrations.CreateModel(
            "Pony",
            [("id", models.AutoField(primary_key=True))],
        )
        # Test the state alteration
        project_state = ProjectState()
        new_state = project_state.clone()
        operation.state_forwards(app_label, new_state)
        # Test the database alteration
        self.assertTableNotExists("%s_pony" % app_label)
        with connection.schema_editor() as editor:
            operation.database_forwards(app_label, editor, project_state, new_state)
        if should_run:
            self.assertTableExists("%s_pony" % app_label)
        else:
            self.assertTableNotExists("%s_pony" % app_label)
        # And test reversal
        with connection.schema_editor() as editor:
            operation.database_backwards(app_label, editor, new_state, project_state)
        self.assertTableNotExists("%s_pony" % app_label) 

def test_rename_model_state_forwards(self):
        """
        RenameModel operations shouldn't trigger the caching of rendered apps
        on state without prior apps.
        """
        state = ProjectState()
        state.add_model(ModelState('migrations', 'Foo', []))
        operation = migrations.RenameModel('Foo', 'Bar')
        operation.state_forwards('migrations', state)
        self.assertNotIn('apps', state.__dict__)
        self.assertNotIn(('migrations', 'foo'), state.models)
        self.assertIn(('migrations', 'bar'), state.models)
        # Now with apps cached.
        apps = state.apps
        operation = migrations.RenameModel('Bar', 'Foo')
        operation.state_forwards('migrations', state)
        self.assertIs(state.apps, apps)
        self.assertNotIn(('migrations', 'bar'), state.models)
        self.assertIn(('migrations', 'foo'), state.models) 

def test_rename_model_state_forwards(self):
        """
        RenameModel operations shouldn't trigger the caching of rendered apps
        on state without prior apps.
        """
        state = ProjectState()
        state.add_model(ModelState('migrations', 'Foo', []))
        operation = migrations.RenameModel('Foo', 'Bar')
        operation.state_forwards('migrations', state)
        self.assertNotIn('apps', state.__dict__)
        self.assertNotIn(('migrations', 'foo'), state.models)
        self.assertIn(('migrations', 'bar'), state.models)
        # Now with apps cached.
        apps = state.apps
        operation = migrations.RenameModel('Bar', 'Foo')
        operation.state_forwards('migrations', state)
        self.assertIs(state.apps, apps)
        self.assertNotIn(('migrations', 'bar'), state.models)
        self.assertIn(('migrations', 'foo'), state.models) 

def _test_create_model(self, app_label, should_run):
        """
        CreateModel honors multi-db settings.
        """
        operation = migrations.CreateModel(
            "Pony",
            [("id", models.AutoField(primary_key=True))],
        )
        # Test the state alteration
        project_state = ProjectState()
        new_state = project_state.clone()
        operation.state_forwards(app_label, new_state)
        # Test the database alteration
        self.assertTableNotExists("%s_pony" % app_label)
        with connection.schema_editor() as editor:
            operation.database_forwards(app_label, editor, project_state, new_state)
        if should_run:
            self.assertTableExists("%s_pony" % app_label)
        else:
            self.assertTableNotExists("%s_pony" % app_label)
        # And test reversal
        with connection.schema_editor() as editor:
            operation.database_backwards(app_label, editor, new_state, project_state)
        self.assertTableNotExists("%s_pony" % app_label) 

def _test_create_model(self, app_label, should_run):
        """
        CreateModel honors multi-db settings.
        """
        operation = migrations.CreateModel(
            "Pony",
            [("id", models.AutoField(primary_key=True))],
        )
        # Test the state alteration
        project_state = ProjectState()
        new_state = project_state.clone()
        operation.state_forwards(app_label, new_state)
        # Test the database alteration
        self.assertTableNotExists("%s_pony" % app_label)
        with connection.schema_editor() as editor:
            operation.database_forwards(app_label, editor, project_state, new_state)
        if should_run:
            self.assertTableExists("%s_pony" % app_label)
        else:
            self.assertTableNotExists("%s_pony" % app_label)
        # And test reversal
        with connection.schema_editor() as editor:
            operation.database_backwards(app_label, editor, new_state, project_state)
        self.assertTableNotExists("%s_pony" % app_label) 

def make_state(self, nodes=None, at_end=True, real_apps=None):
        """
        Given a migration node or nodes, returns a complete ProjectState for it.
        If at_end is False, returns the state before the migration has run.
        If nodes is not provided, returns the overall most current project state.
        """
        if nodes is None:
            nodes = list(self.leaf_nodes())
        if len(nodes) == 0:
            return ProjectState()
        if not isinstance(nodes[0], tuple):
            nodes = [nodes]
        plan = []
        for node in nodes:
            for migration in self.forwards_plan(node):
                if migration not in plan:
                    if not at_end and migration in nodes:
                        continue
                    plan.append(migration)
        project_state = ProjectState(real_apps=real_apps)
        for node in plan:
            project_state = self.nodes[node].mutate_state(project_state, preserve=False)
        return project_state 

def test_install_soname(self):
        """
        Test we can load the 'metadata_lock_info' library.
        """
        assert not plugin_exists("metadata_lock_info")

        state = ProjectState()
        operation = InstallSOName("metadata_lock_info.so")
        assert operation.describe() == "Installs library metadata_lock_info.so"

        new_state = state.clone()
        with connection.schema_editor() as editor:
            operation.database_forwards("testapp", editor, state, new_state)
        assert plugin_exists("metadata_lock_info")

        new_state = state.clone()
        with connection.schema_editor() as editor:
            operation.database_backwards("testapp", editor, new_state, state)
        assert not plugin_exists("metadata_lock_info") 

def test_install_plugin(self):
        """
        Test we can load the example plugin that every version of MySQL ships
        with.
        """
        assert not plugin_exists("metadata_lock_info")

        state = ProjectState()
        operation = InstallPlugin("metadata_lock_info", "metadata_lock_info.so")
        assert (
            operation.describe()
            == "Installs plugin metadata_lock_info from metadata_lock_info.so"
        )
        new_state = state.clone()
        with connection.schema_editor() as editor:
            operation.database_forwards("testapp", editor, state, new_state)

        assert plugin_exists("metadata_lock_info")

        new_state = state.clone()
        with connection.schema_editor() as editor:
            operation.database_backwards("testapp", editor, new_state, state)

        assert not plugin_exists("metadata_lock_info") 

def test_alter_field_reloads_state_on_fk_target_changes(self):
        """
        If AlterField doesn't reload state appropriately, the second AlterField
        crashes on MySQL due to not dropping the PonyRider.pony foreign key
        constraint before modifying the column.
        """
        app_label = 'alter_alter_field_reloads_state_on_fk_target_changes'
        project_state = self.apply_operations(app_label, ProjectState(), operations=[
            migrations.CreateModel('Rider', fields=[
                ('id', models.CharField(primary_key=True, max_length=100)),
            ]),
            migrations.CreateModel('Pony', fields=[
                ('id', models.CharField(primary_key=True, max_length=100)),
                ('rider', models.ForeignKey('%s.Rider' % app_label, models.CASCADE)),
            ]),
            migrations.CreateModel('PonyRider', fields=[
                ('id', models.AutoField(primary_key=True)),
                ('pony', models.ForeignKey('%s.Pony' % app_label, models.CASCADE)),
            ]),
        ])
        project_state = self.apply_operations(app_label, project_state, operations=[
            migrations.AlterField('Rider', 'id', models.CharField(primary_key=True, max_length=99)),
            migrations.AlterField('Pony', 'id', models.CharField(primary_key=True, max_length=99)),
        ]) 

def make_state(self, nodes=None, at_end=True, real_apps=None):
        """
        Given a migration node or nodes, returns a complete ProjectState for it.
        If at_end is False, returns the state before the migration has run.
        If nodes is not provided, returns the overall most current project state.
        """
        if nodes is None:
            nodes = list(self.leaf_nodes())
        if len(nodes) == 0:
            return ProjectState()
        if not isinstance(nodes[0], tuple):
            nodes = [nodes]
        plan = []
        for node in nodes:
            for migration in self.forwards_plan(node):
                if migration not in plan:
                    if not at_end and migration in nodes:
                        continue
                    plan.append(migration)
        project_state = ProjectState(real_apps=real_apps)
        for node in plan:
            project_state = self.nodes[node].mutate_state(project_state, preserve=False)
        return project_state 

def make_state(self, nodes=None, at_end=True, real_apps=None):
        """
        Given a migration node or nodes, return a complete ProjectState for it.
        If at_end is False, return the state before the migration has run.
        If nodes is not provided, return the overall most current project state.
        """
        if nodes is None:
            nodes = list(self.leaf_nodes())
        if not nodes:
            return ProjectState()
        if not isinstance(nodes[0], tuple):
            nodes = [nodes]
        plan = self._generate_plan(nodes, at_end)
        project_state = ProjectState(real_apps=real_apps)
        for node in plan:
            project_state = self.nodes[node].mutate_state(project_state, preserve=False)
        return project_state 

def test_alter_field_reloads_state_on_fk_target_changes(self):
        """
        If AlterField doesn't reload state appropriately, the second AlterField
        crashes on MySQL due to not dropping the PonyRider.pony foreign key
        constraint before modifying the column.
        """
        app_label = 'alter_alter_field_reloads_state_on_fk_target_changes'
        project_state = self.apply_operations(app_label, ProjectState(), operations=[
            migrations.CreateModel('Rider', fields=[
                ('id', models.CharField(primary_key=True, max_length=100)),
            ]),
            migrations.CreateModel('Pony', fields=[
                ('id', models.CharField(primary_key=True, max_length=100)),
                ('rider', models.ForeignKey('%s.Rider' % app_label, models.CASCADE)),
            ]),
            migrations.CreateModel('PonyRider', fields=[
                ('id', models.AutoField(primary_key=True)),
                ('pony', models.ForeignKey('%s.Pony' % app_label, models.CASCADE)),
            ]),
        ])
        project_state = self.apply_operations(app_label, project_state, operations=[
            migrations.AlterField('Rider', 'id', models.CharField(primary_key=True, max_length=99)),
            migrations.AlterField('Pony', 'id', models.CharField(primary_key=True, max_length=99)),
        ]) 

def apply_initial_migration(self, targets: MigrationSpec) -> ProjectState:
        """Reverse back to the original migration."""
        targets = normalize(targets)

        style = no_style()
        # start from clean database state
        sql.drop_models_tables(self._database, style)
        sql.flush_django_migrations_table(self._database, style)

        # prepare as broad plan as possible based on full plan
        self._executor.loader.build_graph()  # reload
        full_plan = self._executor.migration_plan(
            self._executor.loader.graph.leaf_nodes(),
            clean_start=True,
        )
        plan = truncate_plan(targets, full_plan)

        # apply all migrations from generated plan on clean database
        # (only forward, so any unexpected migration won't be applied)
        # to restore database state before tested migration
        return self._migrate(targets, plan=plan) 

def test_rename_model_state_forwards(self):
        """
        RenameModel operations shouldn't trigger the caching of rendered apps
        on state without prior apps.
        """
        state = ProjectState()
        state.add_model(ModelState('migrations', 'Foo', []))
        operation = migrations.RenameModel('Foo', 'Bar')
        operation.state_forwards('migrations', state)
        self.assertNotIn('apps', state.__dict__)
        self.assertNotIn(('migrations', 'foo'), state.models)
        self.assertIn(('migrations', 'bar'), state.models)
        # Now with apps cached.
        apps = state.apps
        operation = migrations.RenameModel('Bar', 'Foo')
        operation.state_forwards('migrations', state)
        self.assertIs(state.apps, apps)
        self.assertNotIn(('migrations', 'bar'), state.models)
        self.assertIn(('migrations', 'foo'), state.models) 

def test_rename_field_reloads_state_on_fk_target_changes(self):
        """
        If RenameField doesn't reload state appropriately, the AlterField
        crashes on MySQL due to not dropping the PonyRider.pony foreign key
        constraint before modifying the column.
        """
        app_label = 'alter_rename_field_reloads_state_on_fk_target_changes'
        project_state = self.apply_operations(app_label, ProjectState(), operations=[
            migrations.CreateModel('Rider', fields=[
                ('id', models.CharField(primary_key=True, max_length=100)),
            ]),
            migrations.CreateModel('Pony', fields=[
                ('id', models.CharField(primary_key=True, max_length=100)),
                ('rider', models.ForeignKey('%s.Rider' % app_label, models.CASCADE)),
            ]),
            migrations.CreateModel('PonyRider', fields=[
                ('id', models.AutoField(primary_key=True)),
                ('pony', models.ForeignKey('%s.Pony' % app_label, models.CASCADE)),
            ]),
        ])
        project_state = self.apply_operations(app_label, project_state, operations=[
            migrations.RenameField('Rider', 'id', 'id2'),
            migrations.AlterField('Pony', 'id', models.CharField(primary_key=True, max_length=99)),
        ], atomic=connection.features.supports_atomic_references_rename) 

def make_state(self, nodes=None, at_end=True, real_apps=None):
        """
        Given a migration node or nodes, return a complete ProjectState for it.
        If at_end is False, return the state before the migration has run.
        If nodes is not provided, return the overall most current project state.
        """
        if nodes is None:
            nodes = list(self.leaf_nodes())
        if len(nodes) == 0:
            return ProjectState()
        if not isinstance(nodes[0], tuple):
            nodes = [nodes]
        plan = []
        for node in nodes:
            for migration in self.forwards_plan(node):
                if migration not in plan:
                    if not at_end and migration in nodes:
                        continue
                    plan.append(migration)
        project_state = ProjectState(real_apps=real_apps)
        for node in plan:
            project_state = self.nodes[node].mutate_state(project_state, preserve=False)
        return project_state 

def make_state(self, nodes=None, at_end=True, real_apps=None):
        """
        Given a migration node or nodes, returns a complete ProjectState for it.
        If at_end is False, returns the state before the migration has run.
        If nodes is not provided, returns the overall most current project state.
        """
        if nodes is None:
            nodes = list(self.leaf_nodes())
        if len(nodes) == 0:
            return ProjectState()
        if not isinstance(nodes[0], tuple):
            nodes = [nodes]
        plan = []
        for node in nodes:
            for migration in self.forwards_plan(node):
                if migration not in plan:
                    if not at_end and migration in nodes:
                        continue
                    plan.append(migration)
        project_state = ProjectState(real_apps=real_apps)
        for node in plan:
            project_state = self.nodes[node].mutate_state(project_state, preserve=False)
        return project_state 

def test_rename_missing_field(self):
        state = ProjectState()
        state.add_model(ModelState('app', 'model', []))
        with self.assertRaisesMessage(FieldDoesNotExist, "app.model has no field named 'field'"):
            migrations.RenameField('model', 'field', 'new_field').state_forwards('app', state) 

def test_alter_field_reloads_state_on_fk_with_to_field_target_changes(self):
        """
        If AlterField doesn't reload state appropriately, the second AlterField
        crashes on MySQL due to not dropping the PonyRider.pony foreign key
        constraint before modifying the column.
        """
        app_label = 'alter_alter_field_reloads_state_on_fk_with_to_field_target_changes'
        project_state = self.apply_operations(app_label, ProjectState(), operations=[
            migrations.CreateModel('Rider', fields=[
                ('id', models.CharField(primary_key=True, max_length=100)),
                ('slug', models.CharField(unique=True, max_length=100)),
            ]),
            migrations.CreateModel('Pony', fields=[
                ('id', models.CharField(primary_key=True, max_length=100)),
                ('rider', models.ForeignKey('%s.Rider' % app_label, models.CASCADE, to_field='slug')),
                ('slug', models.CharField(unique=True, max_length=100)),
            ]),
            migrations.CreateModel('PonyRider', fields=[
                ('id', models.AutoField(primary_key=True)),
                ('pony', models.ForeignKey('%s.Pony' % app_label, models.CASCADE, to_field='slug')),
            ]),
        ])
        project_state = self.apply_operations(app_label, project_state, operations=[
            migrations.AlterField('Rider', 'slug', models.CharField(unique=True, max_length=99)),
            migrations.AlterField('Pony', 'slug', models.CharField(unique=True, max_length=99)),
        ]) 

def test_rename_referenced_field_state_forward(self):
        state = ProjectState()
        state.add_model(ModelState('app', 'Model', [
            ('id', models.AutoField(primary_key=True)),
            ('field', models.IntegerField(unique=True)),
        ]))
        state.add_model(ModelState('app', 'OtherModel', [
            ('id', models.AutoField(primary_key=True)),
            ('fk', models.ForeignKey('Model', models.CASCADE, to_field='field')),
            ('fo', models.ForeignObject('Model', models.CASCADE, from_fields=('fk',), to_fields=('field',))),
        ]))
        operation = migrations.RenameField('Model', 'field', 'renamed')
        new_state = state.clone()
        operation.state_forwards('app', new_state)
        self.assertEqual(new_state.models['app', 'othermodel'].fields[1][1].remote_field.field_name, 'renamed')
        self.assertEqual(new_state.models['app', 'othermodel'].fields[1][1].from_fields, ['self'])
        self.assertEqual(new_state.models['app', 'othermodel'].fields[1][1].to_fields, ('renamed',))
        self.assertEqual(new_state.models['app', 'othermodel'].fields[2][1].from_fields, ('fk',))
        self.assertEqual(new_state.models['app', 'othermodel'].fields[2][1].to_fields, ('renamed',))
        operation = migrations.RenameField('OtherModel', 'fk', 'renamed_fk')
        new_state = state.clone()
        operation.state_forwards('app', new_state)
        self.assertEqual(new_state.models['app', 'othermodel'].fields[1][1].remote_field.field_name, 'renamed')
        self.assertEqual(new_state.models['app', 'othermodel'].fields[1][1].from_fields, ('self',))
        self.assertEqual(new_state.models['app', 'othermodel'].fields[1][1].to_fields, ('renamed',))
        self.assertEqual(new_state.models['app', 'othermodel'].fields[2][1].from_fields, ('renamed_fk',))
        self.assertEqual(new_state.models['app', 'othermodel'].fields[2][1].to_fields, ('renamed',)) 

def test_run_python_noop(self):
        """
        #24098 - Tests no-op RunPython operations.
        """
        project_state = ProjectState()
        new_state = project_state.clone()
        operation = migrations.RunPython(migrations.RunPython.noop, migrations.RunPython.noop)
        with connection.schema_editor() as editor:
            operation.database_forwards("test_runpython", editor, project_state, new_state)
            operation.database_backwards("test_runpython", editor, new_state, project_state) 

def make_project_state(self, model_states):
        "Shortcut to make ProjectStates from lists of predefined models"
        project_state = ProjectState()
        for model_state in model_states:
            project_state.add_model(model_state.clone())
        return project_state 

def _make_project_state(model_states):
    """Shortcut to make :see:ProjectState from a list of predefined models."""

    project_state = ProjectState()
    for model_state in model_states:
        project_state.add_model(model_state.clone())
    return project_state 

def set_up_test_model(self, force_raster_creation=False):
        test_fields = [
            ('id', models.AutoField(primary_key=True)),
            ('name', models.CharField(max_length=100, unique=True)),
            ('geom', fields.MultiPolygonField(srid=4326))
        ]
        if connection.features.supports_raster or force_raster_creation:
            test_fields += [('rast', fields.RasterField(srid=4326, null=True))]
        operations = [migrations.CreateModel('Neighborhood', test_fields)]
        self.current_state = self.apply_operations('gis', ProjectState(), operations) 

def test_rename_m2m_model_after_rename_field(self):
        """RenameModel renames a many-to-many column after a RenameField."""
        app_label = 'test_rename_multiple'
        project_state = self.apply_operations(app_label, ProjectState(), operations=[
            migrations.CreateModel('Pony', fields=[
                ('id', models.AutoField(primary_key=True)),
                ('name', models.CharField(max_length=20)),
            ]),
            migrations.CreateModel('Rider', fields=[
                ('id', models.AutoField(primary_key=True)),
                ('pony', models.ForeignKey('test_rename_multiple.Pony', models.CASCADE)),
            ]),
            migrations.CreateModel('PonyRider', fields=[
                ('id', models.AutoField(primary_key=True)),
                ('riders', models.ManyToManyField('Rider')),
            ]),
            migrations.RenameField(model_name='pony', old_name='name', new_name='fancy_name'),
            migrations.RenameModel(old_name='Rider', new_name='Jockey'),
        ], atomic=connection.features.supports_atomic_references_rename)
        Pony = project_state.apps.get_model(app_label, 'Pony')
        Jockey = project_state.apps.get_model(app_label, 'Jockey')
        PonyRider = project_state.apps.get_model(app_label, 'PonyRider')
        # No "no such column" error means the column was renamed correctly.
        pony = Pony.objects.create(fancy_name='a good name')
        jockey = Jockey.objects.create(pony=pony)
        ponyrider = PonyRider.objects.create()
        ponyrider.riders.add(jockey) 

def test_create_ignore_swapped(self):
        """
        The CreateTable operation ignores swapped models.
        """
        operation = migrations.CreateModel(
            "Pony",
            [
                ("id", models.AutoField(primary_key=True)),
                ("pink", models.IntegerField(default=1)),
            ],
            options={
                "swappable": "TEST_SWAP_MODEL",
            },
        )
        # Test the state alteration (it should still be there!)
        project_state = ProjectState()
        new_state = project_state.clone()
        operation.state_forwards("test_crigsw", new_state)
        self.assertEqual(new_state.models["test_crigsw", "pony"].name, "Pony")
        self.assertEqual(len(new_state.models["test_crigsw", "pony"].fields), 2)
        # Test the database alteration
        self.assertTableNotExists("test_crigsw_pony")
        with connection.schema_editor() as editor:
            operation.database_forwards("test_crigsw", editor, project_state, new_state)
        self.assertTableNotExists("test_crigsw_pony")
        # And test reversal
        with connection.schema_editor() as editor:
            operation.database_backwards("test_crigsw", editor, new_state, project_state)
        self.assertTableNotExists("test_crigsw_pony") 

def test_rename_missing_field(self):
        state = ProjectState()
        state.add_model(ModelState('app', 'model', []))
        with self.assertRaisesMessage(FieldDoesNotExist, "app.model has no field named 'field'"):
            migrations.RenameField('model', 'field', 'new_field').state_forwards('app', state) 

def test_run_python_noop(self):
        """
        #24098 - Tests no-op RunPython operations.
        """
        project_state = ProjectState()
        new_state = project_state.clone()
        operation = migrations.RunPython(migrations.RunPython.noop, migrations.RunPython.noop)
        with connection.schema_editor() as editor:
            operation.database_forwards("test_runpython", editor, project_state, new_state)
            operation.database_backwards("test_runpython", editor, new_state, project_state) 

def test_alter_field_reloads_state_on_fk_with_to_field_target_changes(self):
        """
        If AlterField doesn't reload state appropriately, the second AlterField
        crashes on MySQL due to not dropping the PonyRider.pony foreign key
        constraint before modifying the column.
        """
        app_label = 'alter_alter_field_reloads_state_on_fk_with_to_field_target_changes'
        project_state = self.apply_operations(app_label, ProjectState(), operations=[
            migrations.CreateModel('Rider', fields=[
                ('id', models.CharField(primary_key=True, max_length=100)),
                ('slug', models.CharField(unique=True, max_length=100)),
            ]),
            migrations.CreateModel('Pony', fields=[
                ('id', models.CharField(primary_key=True, max_length=100)),
                ('rider', models.ForeignKey('%s.Rider' % app_label, models.CASCADE, to_field='slug')),
                ('slug', models.CharField(unique=True, max_length=100)),
            ]),
            migrations.CreateModel('PonyRider', fields=[
                ('id', models.AutoField(primary_key=True)),
                ('pony', models.ForeignKey('%s.Pony' % app_label, models.CASCADE, to_field='slug')),
            ]),
        ])
        project_state = self.apply_operations(app_label, project_state, operations=[
            migrations.AlterField('Rider', 'slug', models.CharField(unique=True, max_length=99)),
            migrations.AlterField('Pony', 'slug', models.CharField(unique=True, max_length=99)),
        ])