1. There were no historical records of Homer, and no trustworthy biography of the man exists beyond a few self-referential hints embedded in the texts themselves. 除了作品中包含的一些自我参照的暗示之外,历史上没有关于荷马的记载,也没有该人的可靠传记。
2. Referential integrity for element relationships 元素关系的引用完整性
3. Entering data and verifying referential integrity. 输入数据,并确认参照完整性。
4. That ensures referential integrity between the tables. 这样就保证了表间的引用完整性。
5. Primary key, referential integrity, and check constraints. 主键、引用完整性和检查约束。