The Study And Implementation Of Table-Dependency Analysis In Legacy System

As the fast development of computer technology and rapid changes of business, lots of software systems are turning into legacy systems. So more and more legacy systems, especially legacy databases should be maintained. However, it is difficult for people to understand database design as documents are lost in long years. People usually update a table but not update its references, which leads to the data inconsistency in legacy system. In a word, without the method of table-dependency analysis, the maintenance work will be essentially difficult.Aim at the problem mentioned above, the following work have been done in this paper:Firstly, a method of table-dependency analysis has been worked out. After study the table-dependency in database definition language, procedure, database log and system code, the paper summarizes the common characters of table-dependency and puts forward the method.Secondly, a prototype system of reverse analyzing has been done. The prototype system has implemented lexical analysis, syntax analysis, table-dependency analysis and visualization.In conclusion, this thesis elaborates the problem of table-dependency analysis and provides an effective solution to it. It develops the theories of reverse engineering and could offer great help in maintenance work.