Software development process, the demand for change is inevitable.
There are reasons for changes in demand for a variety of
1, preliminary research is not sufficient demand, leading to misunderstandings demand
2, a description of the customer needs, understanding is not accurate
3, needs analysis poor human capacity, output error needs
4, with the passage of time, changes in demand indeed
Among them, 1 and 2 are more common causes. Also the main reason.
A change in demand, that development is not to be adjusted?
The answer is yes, the purpose of the software is to meet the needs of customers, the software does not meet the customer demand is of no value.
After preliminary research needs, customer needs confirmation, does not mean that the latter can not demand change, needs assessment and validation is just a ritual, he can promote attention to the needs of customers interested parties to confirm, rather than regard it as may have It can no formalized things. After confirming the demand can be changed, but the need to take the change. On behalf of the seriousness of the demand.
The cost of the demand for change that occurred in the end how much. To change the same, some people say is very small, some people say a lot, in the end who is right, how to evaluate. In particular direct customers will not understand: I asked a simple demand, how the development of such a long period?
In the actual development, customer demand changes mentioned, some project personnel, and even the developer directly racking our brains to say, small case, every minute thing, but often it did not, the actual cost of delivery workload doubled.
We have an example to explain why the high cost of changes in demand, changes in demand why the cost is difficult to measure. I do mostly true story of N years ago, a project of this case occurred.
One day the customer came over and said, hoping to increase an organization referred to in the organization table.
why? Because the boss is older and, look bad, font setting up your computer is relatively large, field-organized table there are more, the full name of this column of light tissue accounted for half of the small screen. Because the organization's full name with the group name, such as "▓▓▓▓▓ Human Resources Group Co., Ltd.," 18 characters. Boss only want to show the "Group human resources department," five characters on the line.
The demand for it is reasonable, very reasonable! When the pre-project needs confirmation, when the organization field to confirm missing, or that no one noticed this matter.
After developers and customers to communicate simple, say complex, plus half a day (when asked later, developers say there are 10 reservations a matter of minutes, add a field that is). Customer mumbled statement said, not to add a field, but also for so long, well, I say to the leadership under. Left.
Not for a while, developers say well, also tested.
His job is to do:
1, an increase of tissue referred to as the field in the database: ZZJC, length of 10 characters,
2, the system configuration metadata
3, view and modify tissue interface changes, the full name of the organization referred to later on, the display width of 10.
4, test cleared
5, noon release to manufacturing systems
Then, in the afternoon to tell customers changing for the better. Customer looked, said no problem, that's it.
On this matter so far yet?
….That's good.
The next day the customer has ran: "Why can not a query by referred to the investigation ah?"
Developer: Ok, I'll modify "the system, the form is not what columns you can follow the column of the query is what needs to be configured to open quick and easy configuration interface, you need to configure query configuration id, quick and increase the abbreviation of. .
Afternoon, users sent a shot on qq, organizers said in a query table, department name changed to short, or check out reports of A4 paper open, too wide. Then open the report designer soft sail to find the report, did not find, as in the report registered with the system, modify the name of the report, the actual name of the report with different users see, and open the report registration function, find this report the actual name of the designer to modify, modify the data source sql statement, adding columns on the report, save, publish. End live. But the report is opened in the system, they found width settings, incorrect, and it is in accordance with the adaptive page. :( The original report designer has a bug, once the increase or decrease the column, adaptive his property had changed. In the need to manually modify over .30 minutes later. In order to increase a report on an almost one hour .
Other reports it, it should not be temporary. (Behind this promising dug a hole).
Here are the other changes made after intermittent.
1, the view being given. There is a view used in the organization table, because the table structure changes in the organization of the table, leading to the view state is invalid, unavailable, so this view needs to be rebuilt. For insurance purposes, all views will check it again.
2, there is no record of the change log log referred to the need to modify the trigger. Achieved through the trigger, the new system when the change log of the department referred to, but did not trigger synchronous changes lead to a revision referred to no logging.
3, personnel editing interface, also referred to want to display, rather than the full name, is not necessary.
4. Select the organization of all windows to be modified. To find the filter because according to short.
5, interface. Because it referred to can not be empty, thus providing an interface to the identity of the system to be modified to avoid data issued by the organization are wrong.
6, manual modification.
Finally doing, increase a short, spent at least 10 individual days of the workload. Calculated in accordance ¥ 2000 / person-day costs, a seemingly small changes that bring cost 20,000!
Cost portion 5 comprising:
1, communication costs. Customer needs and frequent communication, in order to fully understand the needs, agreed. Demand not only directly, but also includes indirect requirements (chain reaction)
2, development costs (coding, testing, relevant changes)
3, publishing costs
4, document the cost of change (development of documentation, manuals)
5, the change brought about by mismanagement indirect costs (frequently modified development plan, frequent communication with customers)
This does not consider modifying the program may bring potential bug, bug repair costs, as well as adverse effects.
This thing gives us a lesson:
1, do not underestimate any demand for change.
2, requires experienced staff together to demand change assessment, content assessment: reasonable demand, rising demand chain modifications, all the workload changes.
3, after the completion of the needs assessment, evaluation results should communicate with customers, so that customers understand the need to change the specific content, especially chain reaction, user acceptance and understanding
4, small case, no problem such things to be cautious. Any changes before a careful assessment, is not a small case.
5, developers do not recommend directly with customers. In particular, some rookie.