For large business objects, a map quickly becomes very complex, making it hard to tell which attribute is mapped to which.
对于大型业务对象，映射很快就会变得非常复杂，使得辨别哪些属性映射到哪些属性变得非常困难。
2
Say "the balloon is red," for example, and you will have helped to narrow "red-ness" to being an attribute of the balloon, and not some general property of the world at large.
比如“那个气球是红色的。”，你等于在强调那个红色是气球的某种特质，而不是世界上存在的某样东西。
3
Use of the number attribute can permit a cleaner presentation, particularly of repeats over very large sets of data.