Abstract
In this paper, an IT product sales of the company's information systems project development as the background, discussion of an information system requirements analysis, the whole process, its important features are: the project involved an upgrade replaces the original version of the system.Therefore, different from the needs analysis process to establish a new system, can be divided into three phases: () implementation of the reverse engineering to gain a preliminary understanding of the system; (2) in step 1 to write on the basis of basic needs,Review added by the customer; (3) In step 2, based on prototype, using the prototype with customers and, ultimately, the baseline requirements.In response to these three stages, the paper discusses the analytical methods used and tools as well as some typical problems encountered and measures, and finally on the needs analysis tool used to talk about some of my initial experience.
】 【Body
I in August 1998 to July 2000 participated in a large group of enterprise information systems development work, the large business group mainly related to IT products Invoicing.I am responsible for system analysis in project work, the conglomerate had originally commissioned the development of a computer company had a management system for IT products, but the old system there are two major problems: (a) the system runs very slowly,off for billing, such as sales of goods, from identification to open one to the open one is sometimes necessary to complete 1 to 2 minute response time, so that customers can not tolerate.(B) system data is not accurate, and often severe physical inventory and computer inventory does not match the situation so that the statistical data generated sales of some confusion, the financial data can not effectively use, can only be added by way of manual entry.In this case, the group's general manager decided to refer to the original system to re-develop a system to solve the original system, the existence of these two insurmountable problems.Note; of the original system uses PB6.5 development, database using SYBASE, the server uses Windows2000Server, clients using Windows 98, program structure is used in the traditional C / S structure.
Given the complexity of the Group's business operations, processes, involving staff and more features, and project completion time is short, limited funding and personnel constraints and limited restrictions, bearing in mind the need to avoid the previous system, there have been confusing and difficult to maintain the structural problems, we decided to demand the original system to do a more thorough and realistic analysis, due to the original system has been developed for nearly two years, and customers also have a certain experience, basic business process itself is not muchchange, therefore, we need analysis process is divided into three steps: () analysis of the structure of the original system, the main structure of the database structures and procedures, (2) to obtain (1) step on the basis of the results of basic needs to writereferred to the customer review Buchong, (3) In subsection (2) prototype based on the step, using the prototype with customers, and thus needs to get the final results are available.The following three steps described above were to be addressed.
The first step is to implement the reverse engineering, access to basic needs of the existing system
Since the old system function in general can basically meet the needs of customers, and the development of more than two years have accumulated a lot of experience, so, from which you can get some useful information, but also avoid many detours.At this stage, the main tool we use that comes with PB Power Designer and PB Documents; former is mainly used to analyze the database structure, which is mainly used to analyze the structure of the program, developers and advanced users to easily understand the program.Reasons for using these two tools are: the original system is too large, multi-module, multi-database schema, tables large enough, only by artificial means is difficult to derive a more complete, clear system structure and the overall composition, and the originalsystematic failure to provide correct and complete and effective set of design documents, so we can only rely on tools help to carry out.Analysis of the database using Power Designer, and analysis of the original program with the PB Documents in PBL after the original structure of the system we have a preliminary understanding, combined with the original use of the system, the basic functions and processes identified needs andOn this basis, manually input, generate the initial demand for natural language documents.Here that the use of Power Designer, a downside is: If the fields in a table too, and they also rely on more than one table, the output of the table related graphics are complex, there are many cross, and difficult to adjust, is not convenientread and print.
The second step is based on the first step, that is to write the basic needs of the system, supplemented by the customer review and
The first step of reverse engineering, we get the basic needs of the system.In order to fully record the changing demands and needs of the dependence between the relations, we decided to use Rational's Requisite PRO as our requirements management tool, Rational company has a complete set of tools for requirements management, very powerful, including Requisite Pro, Clear Questetc. These requirements analysis tools to conduct a comprehensive demand management, including record demand changes, dependencies between requirements and so on.However, we consider the full implementation of Rational set of tools will be very expensive and complex, requiring a very strong project management capability to be fully implemented, so we only use a part of one of the most simple functions, it is the record needs to change, record demanddependencies between other related functions with the RUP gave omitted.The reason to do so, mainly on account of project funding, manpower, and the actual situation of the domestic software development.As previously said, we understand and write according to their own basic needs, the review by the client to do well to make the appropriate supplement, we will be finished by the demand for additional formal requirements as the maintenance of records into Requisite Pro database, andclassification of the various needs, set priorities, etc., that work, you can directly from the database clients to understand what the needs put forward so far and what needs must be a priority, which is difficult and so on.In this process, we encountered some problems, such as: Users of our natural language requirements documents are written in many places do not understand, often spent a long time after reading, still do not understand the needs of our description of the process and theirThe complete correspondence between the business; the other is for the first time, Requisite Pro requirements management, classification, determining the property value, some developers do not have experience, resulting in a lot of repetition, for the former, our approachis to find ways to increase the number of diagram, the process will be broken down into small big process, and then repeatedly exchanges and communication with customers, and ultimately achieve the same purpose of mutual understanding.The second question, the reference to a number of examples, combined with the practical use of the property given choice or select, after this phase, we have established the basic needs of libraries, set the basic requirements specification.
The third step is to build a prototype based on the second step, using the prototype with the customer more in-depth exchanges through the exchange needs to modify the corresponding
At this stage of mission work is to report on the second step based on the exchange.We use PB to develop a prototype system to specific business processes and customer communication and communication through the prototype, the customer found that many of our mutual understanding with their variance, we modify the requirements, it is also Requisite Proneeds to modify records in the database history.Proved the role of such records of history are very effective, as there have been two different customer needs to mention the same time the opposite demand, we soon confirmed the historical record of the reference to the wrong customers in thefacts without further debate, while taking advantage of Requisite Pro, we also found a contradiction between some of the demand.After this stage, we finally got through the user acceptance of requirements baseline, that is, the detailed design for the next step the baseline requirements.
In this project, we use Power Designer, PB Documents such as reverse engineering analysis tools and Requisite Pro requirements management tool, the use of these tools so that we improve the work efficiency, played a supporting role.However, for purposes of demand analysis tools.We feel that the domestic application was still too little, this is because not enough attention on the needs analysis, partly because management has not yet reached the appropriate level.Rational demand for the company's complete set of analytical tools, and its function is very powerful, and foreign countries has been in widespread use in the country gradually began to spread, especially those accredited by CMM for more than two units, must use a tool to manage demand.In this project, we only use the Requisite Pro features a number of small areas, the tool has experienced the many benefits of project management.If a power company to the full implementation of RUP, it needs to manage this chronic problem will become less difficult, the project's quality will be improved accordingly.At present, the rise of the CMM boom has been increasing emphasis on needs analysis, requirements analysis is also increasingly used tool, which is very welcome, of course, hope in the near future, can be used on domestic demand analysis tools, then our softwareindustry may actually take off the.
Commentary; the use of reverse engineering tools for re-application of many, this paper presents a practical example.Writing structured, and very practical.Reasonably define the reality of the level of demand analysis.Needs analysis used in the methods and tools are relatively reasonable and scientific.Discussion of the project in the same time to express arguments, using experience, patriotism and dedication.Depth can also be improved, a number of examples should be more abundant.