from __future__ import unicode_literals
from django.db import models
from django.db.models.options import normalize_together
from django.db.migrations.state import ModelState
from django.db.migrations.operations.base import Operation
from django.utils import six
[docs]class CreateModel(Operation):
"""
Create a model's table.
"""
serialization_expand_args = ['fields', 'options']
def __init__(self, name, fields, options=None, bases=None):
self.name = name
self.fields = fields
self.options = options or {}
self.bases = bases or (models.Model,)
def state_forwards(self, app_label, state):
state.models[app_label, self.name.lower()] = ModelState(
app_label,
self.name,
list(self.fields),
dict(self.options),
tuple(self.bases),
)
def database_forwards(self, app_label, schema_editor, from_state, to_state):
apps = to_state.render()
model = apps.get_model(app_label, self.name)
if self.allowed_to_migrate(schema_editor.connection.alias, model):
schema_editor.create_model(model)
def database_backwards(self, app_label, schema_editor, from_state, to_state):
apps = from_state.render()
model = apps.get_model(app_label, self.name)
if self.allowed_to_migrate(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.rel:
if isinstance(field.rel.to, six.string_types):
strings_to_check.append(field.rel.to.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
def __eq__(self, other):
return (
(self.__class__ == other.__class__) and
(self.name == other.name) and
(self.options == other.options) and
(self.bases == other.bases) and
([(k, f.deconstruct()[1:]) for k, f in self.fields] == [(k, f.deconstruct()[1:]) for k, f in other.fields])
)
[docs]class DeleteModel(Operation):
"""
Drops a model's table.
"""
def __init__(self, name):
self.name = name
def state_forwards(self, app_label, state):
del state.models[app_label, self.name.lower()]
def database_forwards(self, app_label, schema_editor, from_state, to_state):
apps = from_state.render()
model = apps.get_model(app_label, self.name)
if self.allowed_to_migrate(schema_editor.connection.alias, model):
schema_editor.delete_model(model)
def database_backwards(self, app_label, schema_editor, from_state, to_state):
apps = to_state.render()
model = apps.get_model(app_label, self.name)
if self.allowed_to_migrate(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
def state_forwards(self, app_label, state):
# Get all of the related objects we need to repoint
apps = state.render(skip_cache=True)
model = apps.get_model(app_label, self.old_name)
related_objects = model._meta.get_all_related_objects()
related_m2m_objects = model._meta.get_all_related_many_to_many_objects()
# 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
del state.models[app_label, self.old_name.lower()]
# Repoint the FKs and M2Ms pointing to us
for related_object in (related_objects + related_m2m_objects):
if related_object.field.rel.to 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.model == model:
related_key = (app_label, self.new_name.lower())
else:
related_key = (
related_object.model._meta.app_label,
related_object.model._meta.object_name.lower(),
)
new_fields = []
for name, field in state.models[related_key].fields:
if name == related_object.field.name:
field = field.clone()
field.rel.to = "%s.%s" % (app_label, self.new_name)
new_fields.append((name, field))
state.models[related_key].fields = new_fields
def database_forwards(self, app_label, schema_editor, from_state, to_state):
new_apps = to_state.render()
new_model = new_apps.get_model(app_label, self.new_name)
if self.allowed_to_migrate(schema_editor.connection.alias, new_model):
old_apps = from_state.render()
old_model = old_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
related_objects = old_model._meta.get_all_related_objects()
related_m2m_objects = old_model._meta.get_all_related_many_to_many_objects()
for related_object in (related_objects + related_m2m_objects):
if related_object.model == old_model:
model = new_model
related_key = (app_label, self.new_name.lower())
else:
model = related_object.model
related_key = (
related_object.model._meta.app_label,
related_object.model._meta.object_name.lower(),
)
to_field = new_apps.get_model(
*related_key
)._meta.get_field_by_name(related_object.field.name)[0]
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.parent_model or not new_field.rel.through._meta.auto_created:
continue
# Rename the M2M table that's based on this model's name.
old_m2m_model = old_field.rel.through
new_m2m_model = new_field.rel.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, self.old_name = self.old_name, self.new_name
self.database_forwards(app_label, schema_editor, from_state, to_state)
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
def state_forwards(self, app_label, state):
state.models[app_label, self.name.lower()].options["db_table"] = self.table
def database_forwards(self, app_label, schema_editor, from_state, to_state):
new_apps = to_state.render()
new_model = new_apps.get_model(app_label, self.name)
if self.allowed_to_migrate(schema_editor.connection.alias, new_model):
old_apps = from_state.render()
old_model = old_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.rel.through._meta.auto_created:
schema_editor.alter_db_table(
new_field.rel.through,
old_field.rel.through._meta.db_table,
new_field.rel.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)
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
def database_forwards(self, app_label, schema_editor, from_state, to_state):
new_apps = to_state.render()
new_model = new_apps.get_model(app_label, self.name)
if self.allowed_to_migrate(schema_editor.connection.alias, new_model):
old_apps = from_state.render()
old_model = old_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 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)
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
def database_forwards(self, app_label, schema_editor, from_state, to_state):
new_apps = to_state.render()
new_model = new_apps.get_model(app_label, self.name)
if self.allowed_to_migrate(schema_editor.connection.alias, new_model):
old_apps = from_state.render()
old_model = old_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 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
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
def database_forwards(self, app_label, schema_editor, from_state, to_state):
to_model = to_state.render().get_model(app_label, self.name)
if self.allowed_to_migrate(schema_editor.connection.alias, to_model):
from_model = from_state.render().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_by_name("_order")[0])
# 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_by_name("_order")[0]
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 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
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]
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, )
Feb 24, 2017