      has_select_for_update_nowait = True
      has_bulk_insert = True
      supports_tablespaces = True
      can_distinct_on_fields = True
  
  class DatabaseWrapper(BaseDatabaseWrapper):
      vendor = 'postgresql'
      operators = {
          'exact': '= %s',
 
</s>
    can_rollback_ddl = True
      has_select_for_update_nowait = True
      has_bulk_insert = True
      supports_tablespaces = True
      can_distinct_on_fields = True
    can_rollback_ddl = True
  
  class DatabaseWrapper(BaseDatabaseWrapper):
      vendor = 'postgresql'
      operators = {
          'exact': '= %s',
keep keep keep add keep keep keep keep keep
 Very start of schema alteration port. Create/delete model and some tests.
django/db/backends/postgresql_psycopg2/base.py