For our second strategy (one table per class hierarchy), you'll have to define your integrity using check constraints.

对于第二个策略(每个类层次结构一个表)，您必须用检测约束定义您自己的完整性。

youdao

Strategy 3: One table per concrete class (Estates).

策略3：每个具体类一个表(estates)。

youdao

Our third and last strategy is probably the most imaginative of all: having one table per concrete class and none for the Estate abstract superclass.

我们的第三个，也是最后一个策略可能是三个策略当中最有想象力的：每个具体类一个表，抽象超类estate没有表。

youdao

You estimate a day to write each database access class and unit test it, so 150 tables at one table per day is 150 days.

估计您每天能编写一个数据库访问类并完成其单元测试，因此，150 个表要用 150天的时间。

youdao

With this approach you create one table per class, the attributes of which are the OID and the attributes that are specific to that class.

使用这种方法，为每个类创建一张表，它的属性是OID和特定于该类的属性。

youdao

With this approach you create one table per class, the attributes of which are the OID and the attributes that are specific to that class.

使用这种方法，为每个类创建一张表，它的属性是OID和特定于该类的属性。

youdao