For example, this might happen when two ore more of the tables in the MQT have a referential integrity relationship defined and the join predicate is on their primary key - foreign key columns.
例如，当MQT中的两个或多个表定义了引用完整性关系并且联结谓词在它们自己的主键-外键列上时，就会出现这种情况。
This category of overhead includes CHECK constraint verification and foreign key constraint (referential integrity (ri)) verification.
这一类的开销包括检查约束验证和外键约束(参照完整性(RI))验证。
Figure 4 depicts the referential integrity (foreign key relationship) shown by a UML association between the tables.
图4描述了由一个表之间的UML关联所表示的引用完整性(外键关系)。
应用推荐