Python models 模块，db() 实例源码

def createdb():
    """
    Session-wide test database.
    :yield models.db: database module for models
    """
    models.__create_tables()  # pylint: disable=protected-access

    yield models.db

    models.__drop_tables()  # pylint: disable=protected-access

def before_request():
    g.db = models.db
    g.db.connect()
    g.user = current_user

def after_request(response):
    g.db.close()
    return response

def init(configObject):
    # this is not unheard of, pygame uses this trick though it's ugly.
    app.config.from_object(configObject)
    from models import db, all_tables
    global db, all_tables
    register_all_blueprints()