摘要: ``When people discuss layering, there's often some confusion over the terms
layer and
tier. Often the two are used as synonyms, but most people see tier as implying a physical separation. Client-server systems are often described as two-tier systems, and the separation is physical: The client is a desktop and the server is a server. I use layer to stress that you don't have to run the layers on different machines. A distinct layer of domain logic often runs on e
阅读全文