重定义为定义已有模式的扩展提供了一种强大的机制，同时也说明了开发具有可扩展性的模式的重要性。
Redefines provide a powerful mechanism for defining extensions to existing schemas, but they also illustrate the importance of developing core schemas with extensibility in mind.
您设计的规则集必须同时具有可扩展性和可重用性。
You have to design your rule base to be extensible and reusable at the same time.
目的在于减少复杂性，并且具有可维护性和可扩展性，同时仍旧提供功能性。
The aim is to reduce complexity, and enable maintainability and extendibility, while still providing the functionality.
应用推荐