Loading django/db/migrations/operations/fields.py +27 −19 Original line number Diff line number Diff line from django.db import router from .base import Operation Loading @@ -17,10 +18,12 @@ class AddField(Operation): def database_forwards(self, app_label, schema_editor, from_state, to_state): from_model = from_state.render().get_model(app_label, self.model_name) to_model = to_state.render().get_model(app_label, self.model_name) if router.allow_migrate(schema_editor.connection.alias, to_model): schema_editor.add_field(from_model, to_model._meta.get_field_by_name(self.name)[0]) def database_backwards(self, app_label, schema_editor, from_state, to_state): from_model = from_state.render().get_model(app_label, self.model_name) if router.allow_migrate(schema_editor.connection.alias, from_model): schema_editor.remove_field(from_model, from_model._meta.get_field_by_name(self.name)[0]) def describe(self): Loading @@ -45,11 +48,13 @@ class RemoveField(Operation): def database_forwards(self, app_label, schema_editor, from_state, to_state): from_model = from_state.render().get_model(app_label, self.model_name) if router.allow_migrate(schema_editor.connection.alias, from_model): schema_editor.remove_field(from_model, from_model._meta.get_field_by_name(self.name)[0]) def database_backwards(self, app_label, schema_editor, from_state, to_state): from_model = from_state.render().get_model(app_label, self.model_name) to_model = to_state.render().get_model(app_label, self.model_name) if router.allow_migrate(schema_editor.connection.alias, to_model): schema_editor.add_field(from_model, to_model._meta.get_field_by_name(self.name)[0]) def describe(self): Loading @@ -74,6 +79,7 @@ class AlterField(Operation): def database_forwards(self, app_label, schema_editor, from_state, to_state): from_model = from_state.render().get_model(app_label, self.model_name) to_model = to_state.render().get_model(app_label, self.model_name) if router.allow_migrate(schema_editor.connection.alias, to_model): schema_editor.alter_field( from_model, from_model._meta.get_field_by_name(self.name)[0], Loading Loading @@ -105,6 +111,7 @@ class RenameField(Operation): def database_forwards(self, app_label, schema_editor, from_state, to_state): from_model = from_state.render().get_model(app_label, self.model_name) to_model = to_state.render().get_model(app_label, self.model_name) if router.allow_migrate(schema_editor.connection.alias, to_model): schema_editor.alter_field( from_model, from_model._meta.get_field_by_name(self.old_name)[0], Loading @@ -114,6 +121,7 @@ class RenameField(Operation): def database_backwards(self, app_label, schema_editor, from_state, to_state): from_model = from_state.render().get_model(app_label, self.model_name) to_model = to_state.render().get_model(app_label, self.model_name) if router.allow_migrate(schema_editor.connection.alias, to_model): schema_editor.alter_field( from_model, from_model._meta.get_field_by_name(self.new_name)[0], Loading django/db/migrations/operations/models.py +39 −22 Original line number Diff line number Diff line from .base import Operation from django.db import models from django.db import models, router from django.db.migrations.state import ModelState Loading @@ -17,13 +17,17 @@ class CreateModel(Operation): def state_forwards(self, app_label, state): state.models[app_label, self.name.lower()] = ModelState(app_label, self.name, self.fields, self.options, self.bases) def database_forwards(self, app, schema_editor, from_state, to_state): def database_forwards(self, app_label, schema_editor, from_state, to_state): app_cache = to_state.render() schema_editor.create_model(app_cache.get_model(app, self.name)) model = app_cache.get_model(app_label, self.name) if router.allow_migrate(schema_editor.connection.alias, model): schema_editor.create_model(model) def database_backwards(self, app, schema_editor, from_state, to_state): def database_backwards(self, app_label, schema_editor, from_state, to_state): app_cache = from_state.render() schema_editor.delete_model(app_cache.get_model(app, self.name)) model = app_cache.get_model(app_label, self.name) if router.allow_migrate(schema_editor.connection.alias, model): schema_editor.delete_model(model) def describe(self): return "Create model %s" % (self.name, ) Loading @@ -42,11 +46,15 @@ class DeleteModel(Operation): def database_forwards(self, app_label, schema_editor, from_state, to_state): app_cache = from_state.render() schema_editor.delete_model(app_cache.get_model(app_label, self.name)) model = app_cache.get_model(app_label, self.name) if router.allow_migrate(schema_editor.connection.alias, model): schema_editor.delete_model(model) def database_backwards(self, app_label, schema_editor, from_state, to_state): app_cache = to_state.render() schema_editor.create_model(app_cache.get_model(app_label, self.name)) model = app_cache.get_model(app_label, self.name) if router.allow_migrate(schema_editor.connection.alias, model): schema_editor.create_model(model) def describe(self): return "Delete model %s" % (self.name, ) Loading @@ -67,10 +75,13 @@ class AlterModelTable(Operation): def database_forwards(self, app_label, schema_editor, from_state, to_state): old_app_cache = from_state.render() new_app_cache = to_state.render() old_model = old_app_cache.get_model(app_label, self.name) new_model = new_app_cache.get_model(app_label, self.name) if router.allow_migrate(schema_editor.connection.alias, new_model): schema_editor.alter_db_table( new_app_cache.get_model(app_label, self.name), old_app_cache.get_model(app_label, self.name)._meta.db_table, new_app_cache.get_model(app_label, self.name)._meta.db_table, new_model, old_model._meta.db_table, new_model._meta.db_table, ) def database_backwards(self, app_label, schema_editor, from_state, to_state): Loading @@ -97,10 +108,13 @@ class AlterUniqueTogether(Operation): def database_forwards(self, app_label, schema_editor, from_state, to_state): old_app_cache = from_state.render() new_app_cache = to_state.render() old_model = old_app_cache.get_model(app_label, self.name) new_model = new_app_cache.get_model(app_label, self.name) if router.allow_migrate(schema_editor.connection.alias, new_model): schema_editor.alter_unique_together( new_app_cache.get_model(app_label, self.name), getattr(old_app_cache.get_model(app_label, self.name)._meta, "unique_together", set()), getattr(new_app_cache.get_model(app_label, self.name)._meta, "unique_together", set()), new_model, getattr(old_model._meta, "unique_together", set()), getattr(new_model._meta, "unique_together", set()), ) def database_backwards(self, app_label, schema_editor, from_state, to_state): Loading @@ -127,10 +141,13 @@ class AlterIndexTogether(Operation): def database_forwards(self, app_label, schema_editor, from_state, to_state): old_app_cache = from_state.render() new_app_cache = to_state.render() old_model = old_app_cache.get_model(app_label, self.name) new_model = new_app_cache.get_model(app_label, self.name) if router.allow_migrate(schema_editor.connection.alias, new_model): schema_editor.alter_index_together( new_app_cache.get_model(app_label, self.name), getattr(old_app_cache.get_model(app_label, self.name)._meta, "index_together", set()), getattr(new_app_cache.get_model(app_label, self.name)._meta, "index_together", set()), new_model, getattr(old_model._meta, "index_together", set()), getattr(new_model._meta, "index_together", set()), ) def database_backwards(self, app_label, schema_editor, from_state, to_state): Loading docs/releases/1.7.txt +12 −0 Original line number Diff line number Diff line Loading @@ -110,6 +110,18 @@ Backwards incompatible changes in 1.7 deprecation timeline for a given feature, its removal may appear as a backwards incompatible change. allow_syncdb/allow_migrate ~~~~~~~~~~~~~~~~~~~~~~~~~~ While Django will still look at ``allow_syncdb`` methods even though they should be renamed to ``allow_migrate``, there is a subtle difference in which models get passed to these methods. For apps with migrations, ``allow_migrate`` will now get passed :ref:`historical models <historical-models>`, which are special versioned models without custom attributes, methods or managers. Make sure your ``allow_migrate`` methods are only referring to fields or other items in ``model._meta``. Miscellaneous ~~~~~~~~~~~~~ Loading docs/topics/db/multi-db.txt +8 −2 Original line number Diff line number Diff line Loading @@ -163,8 +163,14 @@ A database Router is a class that provides up to four methods: the router has no opinion. This method can be used to determine the availability of a model on a given database. Note that if this returns ``True`` for an app with migrations but ``False`` for an app those migrations depend on, Django will error. Note that migrations will just silently not perform any operations on a model for which this returns ``False``. This may result in broken ForeignKeys, extra tables or missing tables if you change it once you have applied some migrations. The value passed for ``model`` may be a :ref:`historical model <historical-models>`, and thus not have any custom attributes, methods or managers. You should only rely on ``_meta``. A router doesn't have to provide *all* these methods -- it may omit one or more of them. If one of the methods is omitted, Django will skip Loading docs/topics/migrations.txt +23 −0 Original line number Diff line number Diff line Loading @@ -272,3 +272,26 @@ Note that this only works given two things: * You have not manually edited your database - Django won't be able to detect that your database doesn't match your models, you'll just get errors when migrations try and modify those tables. .. historical-models: Historical models ----------------- When you run migrations, Django is working from historical versions of your models stored in the migration files. If you write Python code using the ``django.db.migrations.RunPython`` operation, or if you have ``allow_migrate`` methods on your database routers, you will be exposed to these versions of your models. Because it's impossible to serialize arbitrary Python code, these historical models will not have any custom methods or managers that you have defined. They will, however, have the same fields, relationships and ``Meta`` options (also versioned, so they may be different from your current ones). In addition, the base classes of the model are just stored as pointers, so you must always keep base classes around for as long as there is a migration that contains a reference to them. On the plus side, methods and managers from these base classes inherit normally, so if you absolutely need access to these you can opt to move them into a superclass. Loading
django/db/migrations/operations/fields.py +27 −19 Original line number Diff line number Diff line from django.db import router from .base import Operation Loading @@ -17,10 +18,12 @@ class AddField(Operation): def database_forwards(self, app_label, schema_editor, from_state, to_state): from_model = from_state.render().get_model(app_label, self.model_name) to_model = to_state.render().get_model(app_label, self.model_name) if router.allow_migrate(schema_editor.connection.alias, to_model): schema_editor.add_field(from_model, to_model._meta.get_field_by_name(self.name)[0]) def database_backwards(self, app_label, schema_editor, from_state, to_state): from_model = from_state.render().get_model(app_label, self.model_name) if router.allow_migrate(schema_editor.connection.alias, from_model): schema_editor.remove_field(from_model, from_model._meta.get_field_by_name(self.name)[0]) def describe(self): Loading @@ -45,11 +48,13 @@ class RemoveField(Operation): def database_forwards(self, app_label, schema_editor, from_state, to_state): from_model = from_state.render().get_model(app_label, self.model_name) if router.allow_migrate(schema_editor.connection.alias, from_model): schema_editor.remove_field(from_model, from_model._meta.get_field_by_name(self.name)[0]) def database_backwards(self, app_label, schema_editor, from_state, to_state): from_model = from_state.render().get_model(app_label, self.model_name) to_model = to_state.render().get_model(app_label, self.model_name) if router.allow_migrate(schema_editor.connection.alias, to_model): schema_editor.add_field(from_model, to_model._meta.get_field_by_name(self.name)[0]) def describe(self): Loading @@ -74,6 +79,7 @@ class AlterField(Operation): def database_forwards(self, app_label, schema_editor, from_state, to_state): from_model = from_state.render().get_model(app_label, self.model_name) to_model = to_state.render().get_model(app_label, self.model_name) if router.allow_migrate(schema_editor.connection.alias, to_model): schema_editor.alter_field( from_model, from_model._meta.get_field_by_name(self.name)[0], Loading Loading @@ -105,6 +111,7 @@ class RenameField(Operation): def database_forwards(self, app_label, schema_editor, from_state, to_state): from_model = from_state.render().get_model(app_label, self.model_name) to_model = to_state.render().get_model(app_label, self.model_name) if router.allow_migrate(schema_editor.connection.alias, to_model): schema_editor.alter_field( from_model, from_model._meta.get_field_by_name(self.old_name)[0], Loading @@ -114,6 +121,7 @@ class RenameField(Operation): def database_backwards(self, app_label, schema_editor, from_state, to_state): from_model = from_state.render().get_model(app_label, self.model_name) to_model = to_state.render().get_model(app_label, self.model_name) if router.allow_migrate(schema_editor.connection.alias, to_model): schema_editor.alter_field( from_model, from_model._meta.get_field_by_name(self.new_name)[0], Loading
django/db/migrations/operations/models.py +39 −22 Original line number Diff line number Diff line from .base import Operation from django.db import models from django.db import models, router from django.db.migrations.state import ModelState Loading @@ -17,13 +17,17 @@ class CreateModel(Operation): def state_forwards(self, app_label, state): state.models[app_label, self.name.lower()] = ModelState(app_label, self.name, self.fields, self.options, self.bases) def database_forwards(self, app, schema_editor, from_state, to_state): def database_forwards(self, app_label, schema_editor, from_state, to_state): app_cache = to_state.render() schema_editor.create_model(app_cache.get_model(app, self.name)) model = app_cache.get_model(app_label, self.name) if router.allow_migrate(schema_editor.connection.alias, model): schema_editor.create_model(model) def database_backwards(self, app, schema_editor, from_state, to_state): def database_backwards(self, app_label, schema_editor, from_state, to_state): app_cache = from_state.render() schema_editor.delete_model(app_cache.get_model(app, self.name)) model = app_cache.get_model(app_label, self.name) if router.allow_migrate(schema_editor.connection.alias, model): schema_editor.delete_model(model) def describe(self): return "Create model %s" % (self.name, ) Loading @@ -42,11 +46,15 @@ class DeleteModel(Operation): def database_forwards(self, app_label, schema_editor, from_state, to_state): app_cache = from_state.render() schema_editor.delete_model(app_cache.get_model(app_label, self.name)) model = app_cache.get_model(app_label, self.name) if router.allow_migrate(schema_editor.connection.alias, model): schema_editor.delete_model(model) def database_backwards(self, app_label, schema_editor, from_state, to_state): app_cache = to_state.render() schema_editor.create_model(app_cache.get_model(app_label, self.name)) model = app_cache.get_model(app_label, self.name) if router.allow_migrate(schema_editor.connection.alias, model): schema_editor.create_model(model) def describe(self): return "Delete model %s" % (self.name, ) Loading @@ -67,10 +75,13 @@ class AlterModelTable(Operation): def database_forwards(self, app_label, schema_editor, from_state, to_state): old_app_cache = from_state.render() new_app_cache = to_state.render() old_model = old_app_cache.get_model(app_label, self.name) new_model = new_app_cache.get_model(app_label, self.name) if router.allow_migrate(schema_editor.connection.alias, new_model): schema_editor.alter_db_table( new_app_cache.get_model(app_label, self.name), old_app_cache.get_model(app_label, self.name)._meta.db_table, new_app_cache.get_model(app_label, self.name)._meta.db_table, new_model, old_model._meta.db_table, new_model._meta.db_table, ) def database_backwards(self, app_label, schema_editor, from_state, to_state): Loading @@ -97,10 +108,13 @@ class AlterUniqueTogether(Operation): def database_forwards(self, app_label, schema_editor, from_state, to_state): old_app_cache = from_state.render() new_app_cache = to_state.render() old_model = old_app_cache.get_model(app_label, self.name) new_model = new_app_cache.get_model(app_label, self.name) if router.allow_migrate(schema_editor.connection.alias, new_model): schema_editor.alter_unique_together( new_app_cache.get_model(app_label, self.name), getattr(old_app_cache.get_model(app_label, self.name)._meta, "unique_together", set()), getattr(new_app_cache.get_model(app_label, self.name)._meta, "unique_together", set()), new_model, getattr(old_model._meta, "unique_together", set()), getattr(new_model._meta, "unique_together", set()), ) def database_backwards(self, app_label, schema_editor, from_state, to_state): Loading @@ -127,10 +141,13 @@ class AlterIndexTogether(Operation): def database_forwards(self, app_label, schema_editor, from_state, to_state): old_app_cache = from_state.render() new_app_cache = to_state.render() old_model = old_app_cache.get_model(app_label, self.name) new_model = new_app_cache.get_model(app_label, self.name) if router.allow_migrate(schema_editor.connection.alias, new_model): schema_editor.alter_index_together( new_app_cache.get_model(app_label, self.name), getattr(old_app_cache.get_model(app_label, self.name)._meta, "index_together", set()), getattr(new_app_cache.get_model(app_label, self.name)._meta, "index_together", set()), new_model, getattr(old_model._meta, "index_together", set()), getattr(new_model._meta, "index_together", set()), ) def database_backwards(self, app_label, schema_editor, from_state, to_state): Loading
docs/releases/1.7.txt +12 −0 Original line number Diff line number Diff line Loading @@ -110,6 +110,18 @@ Backwards incompatible changes in 1.7 deprecation timeline for a given feature, its removal may appear as a backwards incompatible change. allow_syncdb/allow_migrate ~~~~~~~~~~~~~~~~~~~~~~~~~~ While Django will still look at ``allow_syncdb`` methods even though they should be renamed to ``allow_migrate``, there is a subtle difference in which models get passed to these methods. For apps with migrations, ``allow_migrate`` will now get passed :ref:`historical models <historical-models>`, which are special versioned models without custom attributes, methods or managers. Make sure your ``allow_migrate`` methods are only referring to fields or other items in ``model._meta``. Miscellaneous ~~~~~~~~~~~~~ Loading
docs/topics/db/multi-db.txt +8 −2 Original line number Diff line number Diff line Loading @@ -163,8 +163,14 @@ A database Router is a class that provides up to four methods: the router has no opinion. This method can be used to determine the availability of a model on a given database. Note that if this returns ``True`` for an app with migrations but ``False`` for an app those migrations depend on, Django will error. Note that migrations will just silently not perform any operations on a model for which this returns ``False``. This may result in broken ForeignKeys, extra tables or missing tables if you change it once you have applied some migrations. The value passed for ``model`` may be a :ref:`historical model <historical-models>`, and thus not have any custom attributes, methods or managers. You should only rely on ``_meta``. A router doesn't have to provide *all* these methods -- it may omit one or more of them. If one of the methods is omitted, Django will skip Loading
docs/topics/migrations.txt +23 −0 Original line number Diff line number Diff line Loading @@ -272,3 +272,26 @@ Note that this only works given two things: * You have not manually edited your database - Django won't be able to detect that your database doesn't match your models, you'll just get errors when migrations try and modify those tables. .. historical-models: Historical models ----------------- When you run migrations, Django is working from historical versions of your models stored in the migration files. If you write Python code using the ``django.db.migrations.RunPython`` operation, or if you have ``allow_migrate`` methods on your database routers, you will be exposed to these versions of your models. Because it's impossible to serialize arbitrary Python code, these historical models will not have any custom methods or managers that you have defined. They will, however, have the same fields, relationships and ``Meta`` options (also versioned, so they may be different from your current ones). In addition, the base classes of the model are just stored as pointers, so you must always keep base classes around for as long as there is a migration that contains a reference to them. On the plus side, methods and managers from these base classes inherit normally, so if you absolutely need access to these you can opt to move them into a superclass.
