所以，在book表这个示例中，有一个主键字段叫做book_id。

So, in the case of the book table, there is a primary key field called book_id.

youdao

代码的惟一假设就是只有一个主键字段，而且这个字段的名称是表名加上_ id。

The only assumptions the code makes is that there is a single primary key field and that the name of that field is the name of the table plus _id.

youdao

描述符也可以提供与注释相同的有关实体的元数据信息，如主键字段，以及对象之间的任何映射。

The descriptor can also provide the same metadata information about the entities as annotations, such as primary key field, and any mappings between objects.

youdao