[6.1.1一对一映射](6.1.1%E4%B8%80%E5%AF%B9%E4%B8%80%E6%98%A0%E5%B0%84.md) [6.1.2一对多映射](6.1.2%E4%B8%80%E5%AF%B9%E5%A4%9A%E6%98%A0%E5%B0%84.md) [6.1.3鉴别器查询](6.1.3%E9%89%B4%E5%88%AB%E5%99%A8%E6%9F%A5%E8%AF%A2.md)