声明性基础和 ORM 映射函数（如 ORM 映射类配置 中所述）是 ORM 的主要配置接口。一旦映射配置完成，持久化操作的主要使用接口是 Session。
The declarative base and ORM mapping functions described at
ORM 映射类配置 are the primary configurational interface for the
ORM. Once mappings are configured, the primary usage interface for
persistence operations is the
Session.