Source code for django.db.migrations.operations.models
from django.db import models
from django.db.migrations.operations.base import Operation
from django.db.migrations.state import ModelState
from django.db.migrations.utils import field_references, resolve_relation
from django.db.models.options import normalize_together
from django.utils.functional import cached_property
from .fields import AddField, AlterField, FieldOperation, RemoveField, RenameField
def _check_for_duplicates(arg_name, objs):
used_vals = set()
for val in objs:
if val in used_vals:
raise ValueError(
"Found duplicate value %s in CreateModel %s argument." % (val, arg_name)
)
used_vals.add(val)
class ModelOperation(Operation):
def __init__(self, name):
self.name = name
@cached_property
def name_lower(self):
return self.name.lower()
def references_model(self, name, app_label):
return name.lower() == self.name_lower
def reduce(self, operation, app_label):
return super().reduce(operation, app_label) or self.can_reduce_through(
operation, app_label
)
def can_reduce_through(self, operation, app_label):
return not operation.references_model(self.name, app_label)
[docs]
class CreateModel(ModelOperation):
"""Create a model's table."""
serialization_expand_args = ["fields", "options", "managers"]
def __init__(self, name, fields, options=None, bases=None, managers=None):
self.fields = fields
self.options = options or {}
self.bases = bases or (models.Model,)
self.managers = managers or []
super().__init__(name)
# Sanity-check that there are no duplicated field names, bases, or
# manager names
_check_for_duplicates("fields", (name for name, _ in self.fields))
_check_for_duplicates(
"bases",
(
base._meta.label_lower
if hasattr(base, "_meta")
else base.lower()
if isinstance(base, str)
else base
for base in self.bases
),
)
_check_for_duplicates("managers", (name for name, _ in self.managers))
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__.__qualname__, [], 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,
)
@property
def migration_name_fragment(self):
return self.name_lower
def references_model(self, name, app_label):
name_lower = name.lower()
if name_lower == self.name_lower:
return True
# Check we didn't inherit from the model
reference_model_tuple = (app_label, name_lower)
for base in self.bases:
if (
base is not models.Model
and isinstance(base, (models.base.ModelBase, str))
and resolve_relation(base, app_label) == reference_model_tuple
):
return True
# Check we have no FKs/M2Ms with it
for _name, field in self.fields:
if field_references(
(app_label, self.name_lower), field, reference_model_tuple
):
return True
return False
def reduce(self, operation, app_label):
if (
isinstance(operation, DeleteModel)
and self.name_lower == operation.name_lower
and not self.options.get("proxy", False)
):
return []
elif (
isinstance(operation, RenameModel)
and self.name_lower == operation.old_name_lower
):
return [
CreateModel(
operation.new_name,
fields=self.fields,
options=self.options,
bases=self.bases,
managers=self.managers,
),
]
elif (
isinstance(operation, AlterModelOptions)
and self.name_lower == operation.name_lower
):
options = {**self.options, **operation.options}
for key in operation.ALTER_OPTION_KEYS:
if key not in operation.options:
options.pop(key, None)
return [
CreateModel(
self.name,
fields=self.fields,
options=options,
bases=self.bases,
managers=self.managers,
),
]
elif (
isinstance(operation, AlterModelManagers)
and self.name_lower == operation.name_lower
):
return [
CreateModel(
self.name,
fields=self.fields,
options=self.options,
bases=self.bases,
managers=operation.managers,
),
]
elif (
isinstance(operation, AlterTogetherOptionOperation)
and self.name_lower == operation.name_lower
):
return [
CreateModel(
self.name,
fields=self.fields,
options={
**self.options,
**{operation.option_name: operation.option_value},
},
bases=self.bases,
managers=self.managers,
),
]
elif (
isinstance(operation, AlterOrderWithRespectTo)
and self.name_lower == operation.name_lower
):
return [
CreateModel(
self.name,
fields=self.fields,
options={
**self.options,
"order_with_respect_to": operation.order_with_respect_to,
},
bases=self.bases,
managers=self.managers,
),
]
elif (
isinstance(operation, FieldOperation)
and self.name_lower == operation.model_name_lower
):
if isinstance(operation, AddField):
return [
CreateModel(
self.name,
fields=self.fields + [(operation.name, operation.field)],
options=self.options,
bases=self.bases,
managers=self.managers,
),
]
elif isinstance(operation, AlterField):
return [
CreateModel(
self.name,
fields=[
(n, operation.field if n == operation.name else v)
for n, v in self.fields
],
options=self.options,
bases=self.bases,
managers=self.managers,
),
]
elif isinstance(operation, RemoveField):
options = self.options.copy()
for option_name in ("unique_together", "index_together"):
option = options.pop(option_name, None)
if option:
option = set(
filter(
bool,
(
tuple(
f for f in fields if f != operation.name_lower
)
for fields in option
),
)
)
if option:
options[option_name] = option
order_with_respect_to = options.get("order_with_respect_to")
if order_with_respect_to == operation.name_lower:
del options["order_with_respect_to"]
return [
CreateModel(
self.name,
fields=[
(n, v)
for n, v in self.fields
if n.lower() != operation.name_lower
],
options=options,
bases=self.bases,
managers=self.managers,
),
]
elif isinstance(operation, RenameField):
options = self.options.copy()
for option_name in ("unique_together", "index_together"):
option = options.get(option_name)
if option:
options[option_name] = {
tuple(
operation.new_name if f == operation.old_name else f
for f in fields
)
for fields in option
}
order_with_respect_to = options.get("order_with_respect_to")
if order_with_respect_to == operation.old_name:
options["order_with_respect_to"] = operation.new_name
return [
CreateModel(
self.name,
fields=[
(operation.new_name if n == operation.old_name else n, v)
for n, v in self.fields
],
options=options,
bases=self.bases,
managers=self.managers,
),
]
elif (
isinstance(operation, IndexOperation)
and self.name_lower == operation.model_name_lower
):
if isinstance(operation, AddIndex):
return [
CreateModel(
self.name,
fields=self.fields,
options={
**self.options,
"indexes": [
*self.options.get("indexes", []),
operation.index,
],
},
bases=self.bases,
managers=self.managers,
),
]
elif isinstance(operation, RemoveIndex):
options_indexes = [
index
for index in self.options.get("indexes", [])
if index.name != operation.name
]
return [
CreateModel(
self.name,
fields=self.fields,
options={
**self.options,
"indexes": options_indexes,
},
bases=self.bases,
managers=self.managers,
),
]
elif isinstance(operation, RenameIndex) and operation.old_fields:
options_index_together = {
fields
for fields in self.options.get("index_together", [])
if fields != operation.old_fields
}
if options_index_together:
self.options["index_together"] = options_index_together
else:
self.options.pop("index_together", None)
return [
CreateModel(
self.name,
fields=self.fields,
options={
**self.options,
"indexes": [
*self.options.get("indexes", []),
models.Index(
fields=operation.old_fields, name=operation.new_name
),
],
},
bases=self.bases,
managers=self.managers,
),
]
return super().reduce(operation, app_label)
[docs]
class DeleteModel(ModelOperation):
"""Drop a model's table."""
def deconstruct(self):
kwargs = {
"name": self.name,
}
return (self.__class__.__qualname__, [], 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):
# The deleted model could be referencing the specified model through
# related fields.
return True
def describe(self):
return "Delete model %s" % self.name
@property
def migration_name_fragment(self):
return "delete_%s" % self.name_lower
[docs]
class RenameModel(ModelOperation):
"""Rename a model."""
def __init__(self, old_name, new_name):
self.old_name = old_name
self.new_name = new_name
super().__init__(old_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__.__qualname__, [], kwargs)
def state_forwards(self, app_label, state):
state.rename_model(app_label, self.old_name, self.new_name)
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 columns and the M2M table.
schema_editor._alter_many_to_many(
new_model,
old_field,
new_field,
strict=False,
)
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):
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)
@property
def migration_name_fragment(self):
return "rename_%s_%s" % (self.old_name_lower, self.new_name_lower)
def reduce(self, operation, app_label):
if (
isinstance(operation, RenameModel)
and self.new_name_lower == operation.old_name_lower
):
return [
RenameModel(
self.old_name,
operation.new_name,
),
]
# Skip `ModelOperation.reduce` as we want to run `references_model`
# against self.new_name.
return super(ModelOperation, self).reduce(
operation, app_label
) or not operation.references_model(self.new_name, app_label)
class ModelOptionOperation(ModelOperation):
def reduce(self, operation, app_label):
if (
isinstance(operation, (self.__class__, DeleteModel))
and self.name_lower == operation.name_lower
):
return [operation]
return super().reduce(operation, app_label)
[docs]
class AlterModelTable(ModelOptionOperation):
"""Rename a model's table."""
def __init__(self, name, table):
self.table = table
super().__init__(name)
def deconstruct(self):
kwargs = {
"name": self.name,
"table": self.table,
}
return (self.__class__.__qualname__, [], kwargs)
def state_forwards(self, app_label, state):
state.alter_model_options(app_label, self.name_lower, {"db_table": self.table})
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 describe(self):
return "Rename table for %s to %s" % (
self.name,
self.table if self.table is not None else "(default)",
)
@property
def migration_name_fragment(self):
return "alter_%s_table" % self.name_lower
[docs]
class AlterModelTableComment(ModelOptionOperation):
def __init__(self, name, table_comment):
self.table_comment = table_comment
super().__init__(name)
def deconstruct(self):
kwargs = {
"name": self.name,
"table_comment": self.table_comment,
}
return (self.__class__.__qualname__, [], kwargs)
def state_forwards(self, app_label, state):
state.alter_model_options(
app_label, self.name_lower, {"db_table_comment": self.table_comment}
)
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_comment(
new_model,
old_model._meta.db_table_comment,
new_model._meta.db_table_comment,
)
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 describe(self):
return f"Alter {self.name} table comment"
@property
def migration_name_fragment(self):
return f"alter_{self.name_lower}_table_comment"
class AlterTogetherOptionOperation(ModelOptionOperation):
option_name = None
def __init__(self, name, option_value):
if option_value:
option_value = set(normalize_together(option_value))
setattr(self, self.option_name, option_value)
super().__init__(name)
@cached_property
def option_value(self):
return getattr(self, self.option_name)
def deconstruct(self):
kwargs = {
"name": self.name,
self.option_name: self.option_value,
}
return (self.__class__.__qualname__, [], kwargs)
def state_forwards(self, app_label, state):
state.alter_model_options(
app_label,
self.name_lower,
{self.option_name: self.option_value},
)
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)
alter_together = getattr(schema_editor, "alter_%s" % self.option_name)
alter_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_field(self, model_name, name, app_label):
return self.references_model(model_name, app_label) and (
not self.option_value
or any((name in fields) for fields in self.option_value)
)
def describe(self):
return "Alter %s for %s (%s constraint(s))" % (
self.option_name,
self.name,
len(self.option_value or ""),
)
@property
def migration_name_fragment(self):
return "alter_%s_%s" % (self.name_lower, self.option_name)
def can_reduce_through(self, operation, app_label):
return super().can_reduce_through(operation, app_label) or (
isinstance(operation, AlterTogetherOptionOperation)
and type(operation) is not type(self)
)
[docs]
class AlterUniqueTogether(AlterTogetherOptionOperation):
"""
Change 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):
super().__init__(name, unique_together)
[docs]
class AlterIndexTogether(AlterTogetherOptionOperation):
"""
Change 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):
super().__init__(name, index_together)
[docs]
class AlterOrderWithRespectTo(ModelOptionOperation):
"""Represent a change with the order_with_respect_to option."""
option_name = "order_with_respect_to"
def __init__(self, name, order_with_respect_to):
self.order_with_respect_to = order_with_respect_to
super().__init__(name)
def deconstruct(self):
kwargs = {
"name": self.name,
"order_with_respect_to": self.order_with_respect_to,
}
return (self.__class__.__qualname__, [], kwargs)
def state_forwards(self, app_label, state):
state.alter_model_options(
app_label,
self.name_lower,
{self.option_name: self.order_with_respect_to},
)
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_field(self, model_name, name, app_label):
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,
)
@property
def migration_name_fragment(self):
return "alter_%s_order_with_respect_to" % self.name_lower
[docs]
class AlterModelOptions(ModelOptionOperation):
"""
Set 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 = [
"base_manager_name",
"default_manager_name",
"default_related_name",
"get_latest_by",
"managed",
"ordering",
"permissions",
"default_permissions",
"select_on_save",
"verbose_name",
"verbose_name_plural",
]
def __init__(self, name, options):
self.options = options
super().__init__(name)
def deconstruct(self):
kwargs = {
"name": self.name,
"options": self.options,
}
return (self.__class__.__qualname__, [], kwargs)
def state_forwards(self, app_label, state):
state.alter_model_options(
app_label,
self.name_lower,
self.options,
self.ALTER_OPTION_KEYS,
)
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 describe(self):
return "Change Meta options on %s" % self.name
@property
def migration_name_fragment(self):
return "alter_%s_options" % self.name_lower
[docs]
class AlterModelManagers(ModelOptionOperation):
"""Alter the model's managers."""
serialization_expand_args = ["managers"]
def __init__(self, name, managers):
self.managers = managers
super().__init__(name)
def deconstruct(self):
return (self.__class__.__qualname__, [self.name, self.managers], {})
def state_forwards(self, app_label, state):
state.alter_model_managers(app_label, self.name_lower, self.managers)
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 describe(self):
return "Change managers on %s" % self.name
@property
def migration_name_fragment(self):
return "alter_%s_managers" % self.name_lower
class IndexOperation(Operation):
option_name = "indexes"
@cached_property
def model_name_lower(self):
return self.model_name.lower()
[docs]
class AddIndex(IndexOperation):
"""Add an index on a model."""
def __init__(self, model_name, index):
self.model_name = model_name
if not index.name:
raise ValueError(
"Indexes passed to AddIndex operations require a name "
"argument. %r doesn't have one." % index
)
self.index = index
def state_forwards(self, app_label, state):
state.add_index(app_label, self.model_name_lower, self.index)
def database_forwards(self, app_label, schema_editor, from_state, to_state):
model = to_state.apps.get_model(app_label, self.model_name)
if self.allow_migrate_model(schema_editor.connection.alias, model):
schema_editor.add_index(model, self.index)
def database_backwards(self, app_label, schema_editor, from_state, to_state):
model = from_state.apps.get_model(app_label, self.model_name)
if self.allow_migrate_model(schema_editor.connection.alias, model):
schema_editor.remove_index(model, self.index)
def deconstruct(self):
kwargs = {
"model_name": self.model_name,
"index": self.index,
}
return (
self.__class__.__qualname__,
[],
kwargs,
)
def describe(self):
if self.index.expressions:
return "Create index %s on %s on model %s" % (
self.index.name,
", ".join([str(expression) for expression in self.index.expressions]),
self.model_name,
)
return "Create index %s on field(s) %s of model %s" % (
self.index.name,
", ".join(self.index.fields),
self.model_name,
)
@property
def migration_name_fragment(self):
return "%s_%s" % (self.model_name_lower, self.index.name.lower())
[docs]
class RemoveIndex(IndexOperation):
"""Remove an index from a model."""
def __init__(self, model_name, name):
self.model_name = model_name
self.name = name
def state_forwards(self, app_label, state):
state.remove_index(app_label, self.model_name_lower, self.name)
def database_forwards(self, app_label, schema_editor, from_state, to_state):
model = from_state.apps.get_model(app_label, self.model_name)
if self.allow_migrate_model(schema_editor.connection.alias, model):
from_model_state = from_state.models[app_label, self.model_name_lower]
index = from_model_state.get_index_by_name(self.name)
schema_editor.remove_index(model, index)
def database_backwards(self, app_label, schema_editor, from_state, to_state):
model = to_state.apps.get_model(app_label, self.model_name)
if self.allow_migrate_model(schema_editor.connection.alias, model):
to_model_state = to_state.models[app_label, self.model_name_lower]
index = to_model_state.get_index_by_name(self.name)
schema_editor.add_index(model, index)
def deconstruct(self):
kwargs = {
"model_name": self.model_name,
"name": self.name,
}
return (
self.__class__.__qualname__,
[],
kwargs,
)
def describe(self):
return "Remove index %s from %s" % (self.name, self.model_name)
@property
def migration_name_fragment(self):
return "remove_%s_%s" % (self.model_name_lower, self.name.lower())
[docs]
class RenameIndex(IndexOperation):
"""Rename an index."""
def __init__(self, model_name, new_name, old_name=None, old_fields=None):
if not old_name and not old_fields:
raise ValueError(
"RenameIndex requires one of old_name and old_fields arguments to be "
"set."
)
if old_name and old_fields:
raise ValueError(
"RenameIndex.old_name and old_fields are mutually exclusive."
)
self.model_name = model_name
self.new_name = new_name
self.old_name = old_name
self.old_fields = old_fields
@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 = {
"model_name": self.model_name,
"new_name": self.new_name,
}
if self.old_name:
kwargs["old_name"] = self.old_name
if self.old_fields:
kwargs["old_fields"] = self.old_fields
return (self.__class__.__qualname__, [], kwargs)
def state_forwards(self, app_label, state):
if self.old_fields:
state.add_index(
app_label,
self.model_name_lower,
models.Index(fields=self.old_fields, name=self.new_name),
)
state.remove_model_options(
app_label,
self.model_name_lower,
AlterIndexTogether.option_name,
self.old_fields,
)
else:
state.rename_index(
app_label, self.model_name_lower, self.old_name, self.new_name
)
def database_forwards(self, app_label, schema_editor, from_state, to_state):
model = to_state.apps.get_model(app_label, self.model_name)
if not self.allow_migrate_model(schema_editor.connection.alias, model):
return
if self.old_fields:
from_model = from_state.apps.get_model(app_label, self.model_name)
columns = [
from_model._meta.get_field(field).column for field in self.old_fields
]
matching_index_name = schema_editor._constraint_names(
from_model, column_names=columns, index=True
)
if len(matching_index_name) != 1:
raise ValueError(
"Found wrong number (%s) of indexes for %s(%s)."
% (
len(matching_index_name),
from_model._meta.db_table,
", ".join(columns),
)
)
old_index = models.Index(
fields=self.old_fields,
name=matching_index_name[0],
)
else:
from_model_state = from_state.models[app_label, self.model_name_lower]
old_index = from_model_state.get_index_by_name(self.old_name)
# Don't alter when the index name is not changed.
if old_index.name == self.new_name:
return
to_model_state = to_state.models[app_label, self.model_name_lower]
new_index = to_model_state.get_index_by_name(self.new_name)
schema_editor.rename_index(model, old_index, new_index)
def database_backwards(self, app_label, schema_editor, from_state, to_state):
if self.old_fields:
# Backward operation with unnamed index is a no-op.
return
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 describe(self):
if self.old_name:
return (
f"Rename index {self.old_name} on {self.model_name} to {self.new_name}"
)
return (
f"Rename unnamed index for {self.old_fields} on {self.model_name} to "
f"{self.new_name}"
)
@property
def migration_name_fragment(self):
if self.old_name:
return "rename_%s_%s" % (self.old_name_lower, self.new_name_lower)
return "rename_%s_%s_%s" % (
self.model_name_lower,
"_".join(self.old_fields),
self.new_name_lower,
)
def reduce(self, operation, app_label):
if (
isinstance(operation, RenameIndex)
and self.model_name_lower == operation.model_name_lower
and operation.old_name
and self.new_name_lower == operation.old_name_lower
):
return [
RenameIndex(
self.model_name,
new_name=operation.new_name,
old_name=self.old_name,
old_fields=self.old_fields,
)
]
return super().reduce(operation, app_label)
[docs]
class AddConstraint(IndexOperation):
option_name = "constraints"
def __init__(self, model_name, constraint):
self.model_name = model_name
self.constraint = constraint
def state_forwards(self, app_label, state):
state.add_constraint(app_label, self.model_name_lower, self.constraint)
def database_forwards(self, app_label, schema_editor, from_state, to_state):
model = to_state.apps.get_model(app_label, self.model_name)
if self.allow_migrate_model(schema_editor.connection.alias, model):
schema_editor.add_constraint(model, self.constraint)
def database_backwards(self, app_label, schema_editor, from_state, to_state):
model = to_state.apps.get_model(app_label, self.model_name)
if self.allow_migrate_model(schema_editor.connection.alias, model):
schema_editor.remove_constraint(model, self.constraint)
def deconstruct(self):
return (
self.__class__.__name__,
[],
{
"model_name": self.model_name,
"constraint": self.constraint,
},
)
def describe(self):
return "Create constraint %s on model %s" % (
self.constraint.name,
self.model_name,
)
@property
def migration_name_fragment(self):
return "%s_%s" % (self.model_name_lower, self.constraint.name.lower())
[docs]
class RemoveConstraint(IndexOperation):
option_name = "constraints"
def __init__(self, model_name, name):
self.model_name = model_name
self.name = name
def state_forwards(self, app_label, state):
state.remove_constraint(app_label, self.model_name_lower, self.name)
def database_forwards(self, app_label, schema_editor, from_state, to_state):
model = to_state.apps.get_model(app_label, self.model_name)
if self.allow_migrate_model(schema_editor.connection.alias, model):
from_model_state = from_state.models[app_label, self.model_name_lower]
constraint = from_model_state.get_constraint_by_name(self.name)
schema_editor.remove_constraint(model, constraint)
def database_backwards(self, app_label, schema_editor, from_state, to_state):
model = to_state.apps.get_model(app_label, self.model_name)
if self.allow_migrate_model(schema_editor.connection.alias, model):
to_model_state = to_state.models[app_label, self.model_name_lower]
constraint = to_model_state.get_constraint_by_name(self.name)
schema_editor.add_constraint(model, constraint)
def deconstruct(self):
return (
self.__class__.__name__,
[],
{
"model_name": self.model_name,
"name": self.name,
},
)
def describe(self):
return "Remove constraint %s from model %s" % (self.name, self.model_name)
@property
def migration_name_fragment(self):
return "remove_%s_%s" % (self.model_name_lower, self.name.lower())
