在这种策略下,通过不规则的关系模型支持多态,用一个识别器列(discriminator column)来标识类型信息,将具有相同父类的所有类都映射到一个数据库表中,这些类属性映射的集合组成这个表的列。
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ODS 包含特定的 XML 到关系结构的可视化映射器,来构建带注释的模式,识别如何将给定的 XML 结构映射到关系表和列。
ODS contains a specialized XML-to-relational visual mapper for building annotated schemas that identify how a given XML structure will be mapped to relational tables and columns.
如果 UIMA 注释器的结果大于它们映射到的结果列,那么可能出现难以识别的问题。
Possible problems that are not easy to identify can occur if the results of the UIMA annotator are larger than the result column they are mapped to.
在图12 - 2,在之前本书中学习到的这个界面支持在你的数据库使用列识别器来设计继承。
As you learned earlier in the book, this form of inheritance is supported through the use of a discriminator column in your database as well as the UI, as seen in Figure 12-2.
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