# dialects/__init__.py # Copyright (C) 2005-2025 the SQLAlchemy authors and contributors # # # This module is part of SQLAlchemy and is released under # the MIT License: https://www.opensource.org/licenses/mit-license.php from __future__ import annotations from typing import Callable from typing import Optional from typing import Type from typing import TYPE_CHECKING from .. import util if TYPE_CHECKING: from ..engine.interfaces import Dialect __all__ = ("mssql", "mysql", "oracle", "postgresql", "sqlite") def _auto_fn(name: str) -> Optional[Callable[[], Type[Dialect]]]: """default dialect importer. plugs into the :class:`.PluginLoader` as a first-hit system. """ if "." in name: dialect, driver = name.split(".") else: dialect = name driver = "base" try: if dialect == "mariadb": # it's "OK" for us to hardcode here since _auto_fn is already # hardcoded. if mysql / mariadb etc were third party dialects # they would just publish all the entrypoints, which would actually # look much nicer. module = __import__( "sqlalchemy.dialects.mysql.mariadb" ).dialects.mysql.mariadb return module.loader(driver) # type: ignore else: module = __import__("sqlalchemy.dialects.%s" % (dialect,)).dialects module = getattr(module, dialect) except ImportError: return None if hasattr(module, driver): module = getattr(module, driver) return lambda: module.dialect else: return None registry = util.PluginLoader("sqlalchemy.dialects", auto_fn=_auto_fn) plugins = util.PluginLoader("sqlalchemy.plugins")