239 lines
11 KiB
Python
239 lines
11 KiB
Python
import psycopg2
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from django.db.backends.base.schema import BaseDatabaseSchemaEditor
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from django.db.backends.ddl_references import IndexColumns
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from django.db.backends.utils import strip_quotes
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class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
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sql_create_sequence = "CREATE SEQUENCE %(sequence)s"
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sql_delete_sequence = "DROP SEQUENCE IF EXISTS %(sequence)s CASCADE"
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sql_set_sequence_max = "SELECT setval('%(sequence)s', MAX(%(column)s)) FROM %(table)s"
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sql_set_sequence_owner = 'ALTER SEQUENCE %(sequence)s OWNED BY %(table)s.%(column)s'
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sql_create_index = (
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'CREATE INDEX %(name)s ON %(table)s%(using)s '
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'(%(columns)s)%(include)s%(extra)s%(condition)s'
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)
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sql_create_index_concurrently = (
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'CREATE INDEX CONCURRENTLY %(name)s ON %(table)s%(using)s '
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'(%(columns)s)%(include)s%(extra)s%(condition)s'
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)
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sql_delete_index = "DROP INDEX IF EXISTS %(name)s"
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sql_delete_index_concurrently = "DROP INDEX CONCURRENTLY IF EXISTS %(name)s"
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# Setting the constraint to IMMEDIATE to allow changing data in the same
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# transaction.
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sql_create_column_inline_fk = (
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'CONSTRAINT %(name)s REFERENCES %(to_table)s(%(to_column)s)%(deferrable)s'
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'; SET CONSTRAINTS %(namespace)s%(name)s IMMEDIATE'
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)
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# Setting the constraint to IMMEDIATE runs any deferred checks to allow
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# dropping it in the same transaction.
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sql_delete_fk = "SET CONSTRAINTS %(name)s IMMEDIATE; ALTER TABLE %(table)s DROP CONSTRAINT %(name)s"
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sql_delete_procedure = 'DROP FUNCTION %(procedure)s(%(param_types)s)'
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def quote_value(self, value):
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if isinstance(value, str):
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value = value.replace('%', '%%')
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adapted = psycopg2.extensions.adapt(value)
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if hasattr(adapted, 'encoding'):
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adapted.encoding = 'utf8'
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# getquoted() returns a quoted bytestring of the adapted value.
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return adapted.getquoted().decode()
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def _field_indexes_sql(self, model, field):
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output = super()._field_indexes_sql(model, field)
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like_index_statement = self._create_like_index_sql(model, field)
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if like_index_statement is not None:
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output.append(like_index_statement)
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return output
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def _field_data_type(self, field):
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if field.is_relation:
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return field.rel_db_type(self.connection)
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return self.connection.data_types.get(
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field.get_internal_type(),
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field.db_type(self.connection),
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)
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def _field_base_data_types(self, field):
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# Yield base data types for array fields.
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if field.base_field.get_internal_type() == 'ArrayField':
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yield from self._field_base_data_types(field.base_field)
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else:
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yield self._field_data_type(field.base_field)
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def _create_like_index_sql(self, model, field):
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"""
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Return the statement to create an index with varchar operator pattern
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when the column type is 'varchar' or 'text', otherwise return None.
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"""
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db_type = field.db_type(connection=self.connection)
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if db_type is not None and (field.db_index or field.unique):
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# Fields with database column types of `varchar` and `text` need
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# a second index that specifies their operator class, which is
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# needed when performing correct LIKE queries outside the
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# C locale. See #12234.
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#
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# The same doesn't apply to array fields such as varchar[size]
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# and text[size], so skip them.
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if '[' in db_type:
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return None
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if db_type.startswith('varchar'):
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return self._create_index_sql(
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model,
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fields=[field],
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suffix='_like',
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opclasses=['varchar_pattern_ops'],
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)
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elif db_type.startswith('text'):
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return self._create_index_sql(
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model,
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fields=[field],
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suffix='_like',
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opclasses=['text_pattern_ops'],
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)
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return None
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def _alter_column_type_sql(self, model, old_field, new_field, new_type):
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self.sql_alter_column_type = 'ALTER COLUMN %(column)s TYPE %(type)s'
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# Cast when data type changed.
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using_sql = ' USING %(column)s::%(type)s'
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new_internal_type = new_field.get_internal_type()
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old_internal_type = old_field.get_internal_type()
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if new_internal_type == 'ArrayField' and new_internal_type == old_internal_type:
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# Compare base data types for array fields.
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if list(self._field_base_data_types(old_field)) != list(self._field_base_data_types(new_field)):
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self.sql_alter_column_type += using_sql
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elif self._field_data_type(old_field) != self._field_data_type(new_field):
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self.sql_alter_column_type += using_sql
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# Make ALTER TYPE with SERIAL make sense.
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table = strip_quotes(model._meta.db_table)
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serial_fields_map = {'bigserial': 'bigint', 'serial': 'integer', 'smallserial': 'smallint'}
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if new_type.lower() in serial_fields_map:
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column = strip_quotes(new_field.column)
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sequence_name = "%s_%s_seq" % (table, column)
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return (
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(
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self.sql_alter_column_type % {
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"column": self.quote_name(column),
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"type": serial_fields_map[new_type.lower()],
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},
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[],
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),
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[
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(
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self.sql_delete_sequence % {
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"sequence": self.quote_name(sequence_name),
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},
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[],
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),
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(
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self.sql_create_sequence % {
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"sequence": self.quote_name(sequence_name),
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},
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[],
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),
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(
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self.sql_alter_column % {
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"table": self.quote_name(table),
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"changes": self.sql_alter_column_default % {
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"column": self.quote_name(column),
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"default": "nextval('%s')" % self.quote_name(sequence_name),
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}
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},
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[],
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),
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(
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self.sql_set_sequence_max % {
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"table": self.quote_name(table),
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"column": self.quote_name(column),
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"sequence": self.quote_name(sequence_name),
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},
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[],
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),
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(
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self.sql_set_sequence_owner % {
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'table': self.quote_name(table),
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'column': self.quote_name(column),
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'sequence': self.quote_name(sequence_name),
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},
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[],
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),
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],
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)
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elif old_field.db_parameters(connection=self.connection)['type'] in serial_fields_map:
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# Drop the sequence if migrating away from AutoField.
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column = strip_quotes(new_field.column)
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sequence_name = '%s_%s_seq' % (table, column)
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fragment, _ = super()._alter_column_type_sql(model, old_field, new_field, new_type)
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return fragment, [
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(
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self.sql_delete_sequence % {
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'sequence': self.quote_name(sequence_name),
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},
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[],
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),
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]
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else:
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return super()._alter_column_type_sql(model, old_field, new_field, new_type)
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def _alter_field(self, model, old_field, new_field, old_type, new_type,
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old_db_params, new_db_params, strict=False):
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# Drop indexes on varchar/text/citext columns that are changing to a
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# different type.
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if (old_field.db_index or old_field.unique) and (
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(old_type.startswith('varchar') and not new_type.startswith('varchar')) or
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(old_type.startswith('text') and not new_type.startswith('text')) or
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(old_type.startswith('citext') and not new_type.startswith('citext'))
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):
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index_name = self._create_index_name(model._meta.db_table, [old_field.column], suffix='_like')
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self.execute(self._delete_index_sql(model, index_name))
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super()._alter_field(
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model, old_field, new_field, old_type, new_type, old_db_params,
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new_db_params, strict,
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)
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# Added an index? Create any PostgreSQL-specific indexes.
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if ((not (old_field.db_index or old_field.unique) and new_field.db_index) or
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(not old_field.unique and new_field.unique)):
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like_index_statement = self._create_like_index_sql(model, new_field)
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if like_index_statement is not None:
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self.execute(like_index_statement)
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# Removed an index? Drop any PostgreSQL-specific indexes.
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if old_field.unique and not (new_field.db_index or new_field.unique):
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index_to_remove = self._create_index_name(model._meta.db_table, [old_field.column], suffix='_like')
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self.execute(self._delete_index_sql(model, index_to_remove))
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def _index_columns(self, table, columns, col_suffixes, opclasses):
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if opclasses:
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return IndexColumns(table, columns, self.quote_name, col_suffixes=col_suffixes, opclasses=opclasses)
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return super()._index_columns(table, columns, col_suffixes, opclasses)
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def add_index(self, model, index, concurrently=False):
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self.execute(index.create_sql(model, self, concurrently=concurrently), params=None)
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def remove_index(self, model, index, concurrently=False):
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self.execute(index.remove_sql(model, self, concurrently=concurrently))
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def _delete_index_sql(self, model, name, sql=None, concurrently=False):
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sql = self.sql_delete_index_concurrently if concurrently else self.sql_delete_index
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return super()._delete_index_sql(model, name, sql)
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def _create_index_sql(
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self, model, *, fields=None, name=None, suffix='', using='',
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db_tablespace=None, col_suffixes=(), sql=None, opclasses=(),
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condition=None, concurrently=False, include=None, expressions=None,
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):
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sql = self.sql_create_index if not concurrently else self.sql_create_index_concurrently
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return super()._create_index_sql(
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model, fields=fields, name=name, suffix=suffix, using=using,
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db_tablespace=db_tablespace, col_suffixes=col_suffixes, sql=sql,
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opclasses=opclasses, condition=condition, include=include,
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expressions=expressions,
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)
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