你画活动图前,一定要有use case diagram, 针对use case diagram中的每一个use case,有一个对应的activity diagram(当然有的use case可以继续
细分为sub use case), activity diagram是用来表示一个use case的事件流的,对于你说的怎样来划分分手工需做的和信息系统应该完成的功能说明你对use case diagram和activity diagram的区别还没有弄清楚?对于use case diagram中的每一个use case,都应该有相应的use case description,也就是要对每一个use case进行文档化(documenting),产生的use case description可能象下面这样(引用别人的例子,由于篇幅不能详细写出)
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use case order configured computer
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brief decription this use case allows a customer to
enter a purchase order....
.....
-------------------------------------------------------------------Actors Customer
-------------------------------------------------------------------
Preconditions Customer points an internet browser
to the computer manufacturer's order
entry web page. The page displays the
details of a configured computer to
-gether with its price.
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Main flow The use case begins when the Cust
-omer decides to order the
configured computer by choosing
the Continue(or similarynamed)
function when the order details
are displayed on the screen.
.............................
.............................
.............................
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Alternative flows The Customer activates the Purchase func-
tion before providing all mandatory
information.The system displays anerror
message and it requests that themissing
information be supplied.
The Customer chooses the Reset function
to revert to an empty purchase form.The
system allows the Customer to enter the
information again.
-------------------------------------------------------------------
Postconditions if the use case was successful, the
purchase order is recorded in the system
database. Otherwise, the system's state is
unchanged.
------------------------------------------------------------------
use case description 和activity模型的重要区别是: use case description 是以系统外部(我们要实现的系统)的角色(actor)的视角写的(从上面的叙述性文字可以看出),反映的是actor的活动过程.而 Activity model是从系统内部视角来看的,反映的是系统功能所要完成的动作过程.所以在activity diagram中activities 应该是从系统内部的视角来说的.