Source code for django.db.migrations.operations.models

from __future__ import unicode_literals

from django.db import models
from django.db.migrations.operations.base import Operation
from django.db.migrations.state import ModelState
from django.db.models.options import normalize_together
from django.utils import six
from django.utils.functional import cached_property


[docs]class CreateModel(Operation): """ Create a model's table. """ serialization_expand_args = ['fields', 'options', 'managers'] def __init__(self, name, fields, options=None, bases=None, managers=None): self.name = name self.fields = fields self.options = options or {} self.bases = bases or (models.Model,) self.managers = managers or [] @cached_property def name_lower(self): return self.name.lower() def deconstruct(self): kwargs = { 'name': self.name, 'fields': self.fields, } if self.options: kwargs['options'] = self.options if self.bases and self.bases != (models.Model,): kwargs['bases'] = self.bases if self.managers and self.managers != [('objects', models.Manager())]: kwargs['managers'] = self.managers return ( self.__class__.__name__, [], kwargs ) def state_forwards(self, app_label, state): state.add_model(ModelState( app_label, self.name, list(self.fields), dict(self.options), tuple(self.bases), list(self.managers), )) def database_forwards(self, app_label, schema_editor, from_state, to_state): model = to_state.apps.get_model(app_label, self.name) if self.allow_migrate_model(schema_editor.connection.alias, model): schema_editor.create_model(model) def database_backwards(self, app_label, schema_editor, from_state, to_state): model = from_state.apps.get_model(app_label, self.name) if self.allow_migrate_model(schema_editor.connection.alias, model): schema_editor.delete_model(model) def describe(self): return "Create %smodel %s" % ("proxy " if self.options.get("proxy", False) else "", self.name) def references_model(self, name, app_label=None): strings_to_check = [self.name] # Check we didn't inherit from the model for base in self.bases: if isinstance(base, six.string_types): strings_to_check.append(base.split(".")[-1]) # Check we have no FKs/M2Ms with it for fname, field in self.fields: if field.remote_field: if isinstance(field.remote_field.model, six.string_types): strings_to_check.append(field.remote_field.model.split(".")[-1]) # Now go over all the strings and compare them for string in strings_to_check: if string.lower() == name.lower(): return True return False
[docs]class DeleteModel(Operation): """ Drops a model's table. """ def __init__(self, name): self.name = name @cached_property def name_lower(self): return self.name.lower() def deconstruct(self): kwargs = { 'name': self.name, } return ( self.__class__.__name__, [], kwargs ) def state_forwards(self, app_label, state): state.remove_model(app_label, self.name_lower) def database_forwards(self, app_label, schema_editor, from_state, to_state): model = from_state.apps.get_model(app_label, self.name) if self.allow_migrate_model(schema_editor.connection.alias, model): schema_editor.delete_model(model) def database_backwards(self, app_label, schema_editor, from_state, to_state): model = to_state.apps.get_model(app_label, self.name) if self.allow_migrate_model(schema_editor.connection.alias, model): schema_editor.create_model(model) def references_model(self, name, app_label=None): return name.lower() == self.name_lower def describe(self): return "Delete model %s" % (self.name, )
[docs]class RenameModel(Operation): """ Renames a model. """ def __init__(self, old_name, new_name): self.old_name = old_name self.new_name = new_name @cached_property def old_name_lower(self): return self.old_name.lower() @cached_property def new_name_lower(self): return self.new_name.lower() def deconstruct(self): kwargs = { 'old_name': self.old_name, 'new_name': self.new_name, } return ( self.__class__.__name__, [], kwargs ) def state_forwards(self, app_label, state): apps = state.apps model = apps.get_model(app_label, self.old_name) model._meta.apps = apps # Get all of the related objects we need to repoint all_related_objects = ( f for f in model._meta.get_fields(include_hidden=True) if f.auto_created and not f.concrete and (not f.hidden or f.many_to_many) ) # Rename the model state.models[app_label, self.new_name_lower] = state.models[app_label, self.old_name_lower] state.models[app_label, self.new_name_lower].name = self.new_name state.remove_model(app_label, self.old_name_lower) # Repoint the FKs and M2Ms pointing to us for related_object in all_related_objects: if related_object.model is not model: # The model being renamed does not participate in this relation # directly. Rather, a superclass does. continue # Use the new related key for self referential related objects. if related_object.related_model == model: related_key = (app_label, self.new_name_lower) else: related_key = ( related_object.related_model._meta.app_label, related_object.related_model._meta.model_name, ) new_fields = [] for name, field in state.models[related_key].fields: if name == related_object.field.name: field = field.clone() field.remote_field.model = "%s.%s" % (app_label, self.new_name) new_fields.append((name, field)) state.models[related_key].fields = new_fields state.reload_model(*related_key) state.reload_model(app_label, self.new_name_lower) def database_forwards(self, app_label, schema_editor, from_state, to_state): new_model = to_state.apps.get_model(app_label, self.new_name) if self.allow_migrate_model(schema_editor.connection.alias, new_model): old_model = from_state.apps.get_model(app_label, self.old_name) # Move the main table schema_editor.alter_db_table( new_model, old_model._meta.db_table, new_model._meta.db_table, ) # Alter the fields pointing to us for related_object in old_model._meta.related_objects: if related_object.related_model == old_model: model = new_model related_key = (app_label, self.new_name_lower) else: model = related_object.related_model related_key = ( related_object.related_model._meta.app_label, related_object.related_model._meta.model_name, ) to_field = to_state.apps.get_model( *related_key )._meta.get_field(related_object.field.name) schema_editor.alter_field( model, related_object.field, to_field, ) # Rename M2M fields whose name is based on this model's name. fields = zip(old_model._meta.local_many_to_many, new_model._meta.local_many_to_many) for (old_field, new_field) in fields: # Skip self-referential fields as these are renamed above. if new_field.model == new_field.related_model or not new_field.remote_field.through._meta.auto_created: continue # Rename the M2M table that's based on this model's name. old_m2m_model = old_field.remote_field.through new_m2m_model = new_field.remote_field.through schema_editor.alter_db_table( new_m2m_model, old_m2m_model._meta.db_table, new_m2m_model._meta.db_table, ) # Rename the column in the M2M table that's based on this # model's name. schema_editor.alter_field( new_m2m_model, old_m2m_model._meta.get_field(old_model._meta.model_name), new_m2m_model._meta.get_field(new_model._meta.model_name), ) def database_backwards(self, app_label, schema_editor, from_state, to_state): self.new_name_lower, self.old_name_lower = self.old_name_lower, self.new_name_lower self.new_name, self.old_name = self.old_name, self.new_name self.database_forwards(app_label, schema_editor, from_state, to_state) self.new_name_lower, self.old_name_lower = self.old_name_lower, self.new_name_lower self.new_name, self.old_name = self.old_name, self.new_name def references_model(self, name, app_label=None): return ( name.lower() == self.old_name_lower or name.lower() == self.new_name_lower ) def describe(self): return "Rename model %s to %s" % (self.old_name, self.new_name)
[docs]class AlterModelTable(Operation): """ Renames a model's table """ def __init__(self, name, table): self.name = name self.table = table @cached_property def name_lower(self): return self.name.lower() def deconstruct(self): kwargs = { 'name': self.name, 'table': self.table, } return ( self.__class__.__name__, [], kwargs ) def state_forwards(self, app_label, state): state.models[app_label, self.name_lower].options["db_table"] = self.table state.reload_model(app_label, self.name_lower) def database_forwards(self, app_label, schema_editor, from_state, to_state): new_model = to_state.apps.get_model(app_label, self.name) if self.allow_migrate_model(schema_editor.connection.alias, new_model): old_model = from_state.apps.get_model(app_label, self.name) schema_editor.alter_db_table( new_model, old_model._meta.db_table, new_model._meta.db_table, ) # Rename M2M fields whose name is based on this model's db_table for (old_field, new_field) in zip(old_model._meta.local_many_to_many, new_model._meta.local_many_to_many): if new_field.remote_field.through._meta.auto_created: schema_editor.alter_db_table( new_field.remote_field.through, old_field.remote_field.through._meta.db_table, new_field.remote_field.through._meta.db_table, ) def database_backwards(self, app_label, schema_editor, from_state, to_state): return self.database_forwards(app_label, schema_editor, from_state, to_state) def references_model(self, name, app_label=None): return name.lower() == self.name_lower def describe(self): return "Rename table for %s to %s" % (self.name, self.table)
[docs]class AlterUniqueTogether(Operation): """ Changes the value of unique_together to the target one. Input value of unique_together must be a set of tuples. """ option_name = "unique_together" def __init__(self, name, unique_together): self.name = name unique_together = normalize_together(unique_together) self.unique_together = set(tuple(cons) for cons in unique_together) @cached_property def name_lower(self): return self.name.lower() def deconstruct(self): kwargs = { 'name': self.name, 'unique_together': self.unique_together, } return ( self.__class__.__name__, [], kwargs ) def state_forwards(self, app_label, state): model_state = state.models[app_label, self.name_lower] model_state.options[self.option_name] = self.unique_together state.reload_model(app_label, self.name_lower) def database_forwards(self, app_label, schema_editor, from_state, to_state): new_model = to_state.apps.get_model(app_label, self.name) if self.allow_migrate_model(schema_editor.connection.alias, new_model): old_model = from_state.apps.get_model(app_label, self.name) schema_editor.alter_unique_together( new_model, getattr(old_model._meta, self.option_name, set()), getattr(new_model._meta, self.option_name, set()), ) def database_backwards(self, app_label, schema_editor, from_state, to_state): return self.database_forwards(app_label, schema_editor, from_state, to_state) def references_model(self, name, app_label=None): return name.lower() == self.name_lower def references_field(self, model_name, name, app_label=None): return ( self.references_model(model_name, app_label) and ( not self.unique_together or any((name in together) for together in self.unique_together) ) ) def describe(self): return "Alter %s for %s (%s constraint(s))" % (self.option_name, self.name, len(self.unique_together or ''))
[docs]class AlterIndexTogether(Operation): """ Changes the value of index_together to the target one. Input value of index_together must be a set of tuples. """ option_name = "index_together" def __init__(self, name, index_together): self.name = name index_together = normalize_together(index_together) self.index_together = set(tuple(cons) for cons in index_together) @cached_property def name_lower(self): return self.name.lower() def deconstruct(self): kwargs = { 'name': self.name, 'index_together': self.index_together, } return ( self.__class__.__name__, [], kwargs ) def state_forwards(self, app_label, state): model_state = state.models[app_label, self.name_lower] model_state.options[self.option_name] = self.index_together state.reload_model(app_label, self.name_lower) def database_forwards(self, app_label, schema_editor, from_state, to_state): new_model = to_state.apps.get_model(app_label, self.name) if self.allow_migrate_model(schema_editor.connection.alias, new_model): old_model = from_state.apps.get_model(app_label, self.name) schema_editor.alter_index_together( new_model, getattr(old_model._meta, self.option_name, set()), getattr(new_model._meta, self.option_name, set()), ) def database_backwards(self, app_label, schema_editor, from_state, to_state): return self.database_forwards(app_label, schema_editor, from_state, to_state) def references_model(self, name, app_label=None): return name.lower() == self.name_lower def references_field(self, model_name, name, app_label=None): return ( self.references_model(model_name, app_label) and ( not self.index_together or any((name in together) for together in self.index_together) ) ) def describe(self): return "Alter %s for %s (%s constraint(s))" % (self.option_name, self.name, len(self.index_together or ''))
[docs]class AlterOrderWithRespectTo(Operation): """ Represents a change with the order_with_respect_to option. """ def __init__(self, name, order_with_respect_to): self.name = name self.order_with_respect_to = order_with_respect_to @cached_property def name_lower(self): return self.name.lower() def deconstruct(self): kwargs = { 'name': self.name, 'order_with_respect_to': self.order_with_respect_to, } return ( self.__class__.__name__, [], kwargs ) def state_forwards(self, app_label, state): model_state = state.models[app_label, self.name_lower] model_state.options['order_with_respect_to'] = self.order_with_respect_to state.reload_model(app_label, self.name_lower) def database_forwards(self, app_label, schema_editor, from_state, to_state): to_model = to_state.apps.get_model(app_label, self.name) if self.allow_migrate_model(schema_editor.connection.alias, to_model): from_model = from_state.apps.get_model(app_label, self.name) # Remove a field if we need to if from_model._meta.order_with_respect_to and not to_model._meta.order_with_respect_to: schema_editor.remove_field(from_model, from_model._meta.get_field("_order")) # Add a field if we need to (altering the column is untouched as # it's likely a rename) elif to_model._meta.order_with_respect_to and not from_model._meta.order_with_respect_to: field = to_model._meta.get_field("_order") if not field.has_default(): field.default = 0 schema_editor.add_field( from_model, field, ) def database_backwards(self, app_label, schema_editor, from_state, to_state): self.database_forwards(app_label, schema_editor, from_state, to_state) def references_model(self, name, app_label=None): return name.lower() == self.name_lower def references_field(self, model_name, name, app_label=None): return ( self.references_model(model_name, app_label) and ( self.order_with_respect_to is None or name == self.order_with_respect_to ) ) def describe(self): return "Set order_with_respect_to on %s to %s" % (self.name, self.order_with_respect_to)
[docs]class AlterModelOptions(Operation): """ Sets new model options that don't directly affect the database schema (like verbose_name, permissions, ordering). Python code in migrations may still need them. """ # Model options we want to compare and preserve in an AlterModelOptions op ALTER_OPTION_KEYS = [ "get_latest_by", "managed", "ordering", "permissions", "default_permissions", "select_on_save", "verbose_name", "verbose_name_plural", ] def __init__(self, name, options): self.name = name self.options = options @cached_property def name_lower(self): return self.name.lower() def deconstruct(self): kwargs = { 'name': self.name, 'options': self.options, } return ( self.__class__.__name__, [], kwargs ) def state_forwards(self, app_label, state): model_state = state.models[app_label, self.name_lower] model_state.options = dict(model_state.options) model_state.options.update(self.options) for key in self.ALTER_OPTION_KEYS: if key not in self.options and key in model_state.options: del model_state.options[key] state.reload_model(app_label, self.name_lower) def database_forwards(self, app_label, schema_editor, from_state, to_state): pass def database_backwards(self, app_label, schema_editor, from_state, to_state): pass def references_model(self, name, app_label=None): return name.lower() == self.name_lower def describe(self): return "Change Meta options on %s" % (self.name, )
[docs]class AlterModelManagers(Operation): """ Alters the model's managers """ serialization_expand_args = ['managers'] def __init__(self, name, managers): self.name = name self.managers = managers @cached_property def name_lower(self): return self.name.lower() def deconstruct(self): return ( self.__class__.__name__, [self.name, self.managers], {} ) def state_forwards(self, app_label, state): model_state = state.models[app_label, self.name_lower] model_state.managers = list(self.managers) state.reload_model(app_label, self.name_lower) def database_forwards(self, app_label, schema_editor, from_state, to_state): pass def database_backwards(self, app_label, schema_editor, from_state, to_state): pass def references_model(self, name, app_label=None): return name.lower() == self.name_lower def describe(self): return "Change managers on %s" % (self.name, )
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