一边是用户，高商业知识，低软件知识，另一边是程序员，低商业知识，高软件知识，而在中间的，就是分析员、测试员等。同样的道理，越靠近用户，越需要高商业知识，越靠近程序员，越需要高软件知识。因此软件公司未必要有七种员工，从这个角度看，可以有两种（高商业知识或高软件知识），或是三种（高商业知识，中软件知识，高软件知识）而已。
Let us see the SDLC from different angle, U-shape SDLC.
At one end, is the system user, who knows lot of business rules, but almost nothing about computer technicals. The other end, is the programmers, who is the expert of computer technicals, but not the business rules, and those sit in the middles, are analysts, testers, etc. The more the staff near to the user, he need more knowledge of business rules, the more the staff near the programmers, he need to know more about technical knowledge. Thus, a software house not necessary to have 7 types of staff (as according to SDLC), seeing from U-Shape angle, a software house can have either 2 types (high business rules, high technical skills), or 3 types (high business rules, half-half, high technical skills).
