210 lines
9.3 KiB
Python
210 lines
9.3 KiB
Python
import codecs
|
|
import copy
|
|
from decimal import Decimal
|
|
from django.utils import six
|
|
from django.apps.registry import Apps
|
|
from django.db.backends.schema import BaseDatabaseSchemaEditor
|
|
from django.db.models.fields.related import ManyToManyField
|
|
|
|
|
|
class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
|
|
|
|
sql_delete_table = "DROP TABLE %(table)s"
|
|
sql_create_inline_fk = "REFERENCES %(to_table)s (%(to_column)s)"
|
|
|
|
def quote_value(self, value):
|
|
# Inner import to allow nice failure for backend if not present
|
|
import _sqlite3
|
|
try:
|
|
value = _sqlite3.adapt(value)
|
|
except _sqlite3.ProgrammingError:
|
|
pass
|
|
# Manual emulation of SQLite parameter quoting
|
|
if isinstance(value, type(True)):
|
|
return str(int(value))
|
|
elif isinstance(value, (Decimal, float)):
|
|
return str(value)
|
|
elif isinstance(value, six.integer_types):
|
|
return str(value)
|
|
elif isinstance(value, six.string_types):
|
|
return "'%s'" % six.text_type(value).replace("\'", "\'\'")
|
|
elif value is None:
|
|
return "NULL"
|
|
elif isinstance(value, (bytes, bytearray, six.memoryview)):
|
|
# Bytes are only allowed for BLOB fields, encoded as string
|
|
# literals containing hexadecimal data and preceded by a single "X"
|
|
# character:
|
|
# value = b'\x01\x02' => value_hex = b'0102' => return X'0102'
|
|
value = bytes(value)
|
|
hex_encoder = codecs.getencoder('hex_codec')
|
|
value_hex, _length = hex_encoder(value)
|
|
# Use 'ascii' encoding for b'01' => '01', no need to use force_text here.
|
|
return "X'%s'" % value_hex.decode('ascii')
|
|
else:
|
|
raise ValueError("Cannot quote parameter value %r of type %s" % (value, type(value)))
|
|
|
|
def _remake_table(self, model, create_fields=[], delete_fields=[], alter_fields=[], rename_fields=[], override_uniques=None):
|
|
"""
|
|
Shortcut to transform a model from old_model into new_model
|
|
"""
|
|
# Work out the new fields dict / mapping
|
|
body = dict((f.name, f) for f in model._meta.local_fields)
|
|
# Since mapping might mix column names and default values,
|
|
# its values must be already quoted.
|
|
mapping = dict((f.column, self.quote_name(f.column)) for f in model._meta.local_fields)
|
|
# If any of the new or altered fields is introducing a new PK,
|
|
# remove the old one
|
|
restore_pk_field = None
|
|
if any(f.primary_key for f in create_fields) or any(n.primary_key for o, n in alter_fields):
|
|
for name, field in list(body.items()):
|
|
if field.primary_key:
|
|
field.primary_key = False
|
|
restore_pk_field = field
|
|
if field.auto_created:
|
|
del body[name]
|
|
del mapping[field.column]
|
|
# Add in any created fields
|
|
for field in create_fields:
|
|
body[field.name] = field
|
|
# If there's a default, insert it into the copy map
|
|
if field.has_default():
|
|
mapping[field.column] = self.quote_value(
|
|
self.effective_default(field)
|
|
)
|
|
# Add in any altered fields
|
|
for (old_field, new_field) in alter_fields:
|
|
del body[old_field.name]
|
|
del mapping[old_field.column]
|
|
body[new_field.name] = new_field
|
|
mapping[new_field.column] = self.quote_name(old_field.column)
|
|
# Remove any deleted fields
|
|
for field in delete_fields:
|
|
del body[field.name]
|
|
del mapping[field.column]
|
|
# Remove any implicit M2M tables
|
|
if isinstance(field, ManyToManyField) and field.rel.through._meta.auto_created:
|
|
return self.delete_model(field.rel.through)
|
|
# Work inside a new app registry
|
|
apps = Apps()
|
|
|
|
# Provide isolated instances of the fields to the new model body
|
|
# Instantiating the new model with an alternate db_table will alter
|
|
# the internal references of some of the provided fields.
|
|
body = copy.deepcopy(body)
|
|
|
|
# Construct a new model for the new state
|
|
meta_contents = {
|
|
'app_label': model._meta.app_label,
|
|
'db_table': model._meta.db_table + "__new",
|
|
'unique_together': model._meta.unique_together if override_uniques is None else override_uniques,
|
|
'apps': apps,
|
|
}
|
|
meta = type("Meta", tuple(), meta_contents)
|
|
body['Meta'] = meta
|
|
body['__module__'] = model.__module__
|
|
|
|
temp_model = type(model._meta.object_name, model.__bases__, body)
|
|
# Create a new table with that format. We remove things from the
|
|
# deferred SQL that match our table name, too
|
|
self.deferred_sql = [x for x in self.deferred_sql if model._meta.db_table not in x]
|
|
self.create_model(temp_model)
|
|
# Copy data from the old table
|
|
field_maps = list(mapping.items())
|
|
self.execute("INSERT INTO %s (%s) SELECT %s FROM %s" % (
|
|
self.quote_name(temp_model._meta.db_table),
|
|
', '.join(self.quote_name(x) for x, y in field_maps),
|
|
', '.join(y for x, y in field_maps),
|
|
self.quote_name(model._meta.db_table),
|
|
))
|
|
# Delete the old table (not using self.delete_model to avoid deleting
|
|
# all implicit M2M tables)
|
|
self.execute(self.sql_delete_table % {
|
|
"table": self.quote_name(model._meta.db_table),
|
|
})
|
|
# Rename the new to the old
|
|
self.alter_db_table(model, temp_model._meta.db_table, model._meta.db_table)
|
|
# Run deferred SQL on correct table
|
|
for sql in self.deferred_sql:
|
|
self.execute(sql.replace(temp_model._meta.db_table, model._meta.db_table))
|
|
self.deferred_sql = []
|
|
# Fix any PK-removed field
|
|
if restore_pk_field:
|
|
restore_pk_field.primary_key = True
|
|
|
|
def add_field(self, model, field):
|
|
"""
|
|
Creates a field on a model.
|
|
Usually involves adding a column, but may involve adding a
|
|
table instead (for M2M fields)
|
|
"""
|
|
# Special-case implicit M2M tables
|
|
if isinstance(field, ManyToManyField) and field.rel.through._meta.auto_created:
|
|
return self.create_model(field.rel.through)
|
|
self._remake_table(model, create_fields=[field])
|
|
|
|
def remove_field(self, model, field):
|
|
"""
|
|
Removes a field from a model. Usually involves deleting a column,
|
|
but for M2Ms may involve deleting a table.
|
|
"""
|
|
# M2M fields are a special case
|
|
if isinstance(field, ManyToManyField):
|
|
# For implicit M2M tables, delete the auto-created table
|
|
if field.rel.through._meta.auto_created:
|
|
self.delete_model(field.rel.through)
|
|
# For explicit "through" M2M fields, do nothing
|
|
# For everything else, remake.
|
|
else:
|
|
self._remake_table(model, delete_fields=[field])
|
|
|
|
def _alter_field(self, model, old_field, new_field, old_type, new_type, old_db_params, new_db_params, strict=False):
|
|
"""Actually perform a "physical" (non-ManyToMany) field update."""
|
|
# Alter by remaking table
|
|
self._remake_table(model, alter_fields=[(old_field, new_field)])
|
|
|
|
def alter_unique_together(self, model, old_unique_together, new_unique_together):
|
|
"""
|
|
Deals with a model changing its unique_together.
|
|
Note: The input unique_togethers must be doubly-nested, not the single-
|
|
nested ["foo", "bar"] format.
|
|
"""
|
|
self._remake_table(model, override_uniques=new_unique_together)
|
|
|
|
def _alter_many_to_many(self, model, old_field, new_field, strict):
|
|
"""
|
|
Alters M2Ms to repoint their to= endpoints.
|
|
"""
|
|
if old_field.rel.through._meta.db_table == new_field.rel.through._meta.db_table:
|
|
# The field name didn't change, but some options did; we have to propagate this altering.
|
|
self._remake_table(
|
|
old_field.rel.through,
|
|
alter_fields=[(
|
|
# We need the field that points to the target model, so we can tell alter_field to change it -
|
|
# this is m2m_reverse_field_name() (as opposed to m2m_field_name, which points to our model)
|
|
old_field.rel.through._meta.get_field_by_name(old_field.m2m_reverse_field_name())[0],
|
|
new_field.rel.through._meta.get_field_by_name(new_field.m2m_reverse_field_name())[0],
|
|
)],
|
|
override_uniques=(new_field.m2m_field_name(), new_field.m2m_reverse_field_name()),
|
|
)
|
|
return
|
|
|
|
# Make a new through table
|
|
self.create_model(new_field.rel.through)
|
|
# Copy the data across
|
|
self.execute("INSERT INTO %s (%s) SELECT %s FROM %s" % (
|
|
self.quote_name(new_field.rel.through._meta.db_table),
|
|
', '.join([
|
|
"id",
|
|
new_field.m2m_column_name(),
|
|
new_field.m2m_reverse_name(),
|
|
]),
|
|
', '.join([
|
|
"id",
|
|
old_field.m2m_column_name(),
|
|
old_field.m2m_reverse_name(),
|
|
]),
|
|
self.quote_name(old_field.rel.through._meta.db_table),
|
|
))
|
|
# Delete the old through table
|
|
self.delete_model(old_field.rel.through)
|