# File lib/dm-constraints/adapters/dm-do-adapter.rb, line 17
        def constraint_exists?(storage_name, constraint_name)
          statement = "SELECT COUNT(*)\nFROM \"information_schema\".\"table_constraints\"\nWHERE \"constraint_type\" = 'FOREIGN KEY'\nAND \"table_schema\" = ?\nAND \"table_name\" = ?\nAND \"constraint_name\" = ?\n".compress_lines

          select(statement, schema_name, storage_name, constraint_name).first > 0
        end