If you understand the business functions and the information flow within a corporate job or corporate department, you will understand the purpose and basic content of all the computer programs that have been written to support them. But what s the best way to work with a program fat with thousands of lines of source code?
You can master existing complex programs ”programs with tens of thousands of lines of source code. All you need to do is adopt the systematic approach I outline in this chapter, which includes both walking through the business process and then placing audit statements liberally throughout the code. Doing both successfully will make you a valuable member of your programming team.
My approach to mastering millions of lines of code, which is usually written in the primary programming language of the company, is to start with a business function that I know. This is simple: You probably know many of the essential company business processes from your personal life or from what you ve learned in school or a previous job. If you ve worked in a business and been observant, you understand how a company operates.
When I took over programming responsibility for the support and enhancement of a huge warehouse distribution packing system, I didn t need to understand how 400 packers worked; all I had to know was how a single packer worked. So the systems analyst in charge and I walked out to a local warehouse and watched a packer barcode -scanning items into cartons with a radio frequency scanner. There were some more details, but I made sure I understood the business function and some needs that were not being currently addressed by the programs before I even looked at programs or code.
So the very first step you must take is to visualize the business process by actually walking through it. (I mean that you should understand the process so well that you can conjure up in your mind images of employees performing the tasks .) If the application is a very familiar one, such as accounts payable, you probably already know the process from having worked on a similar application. Nevertheless, I still recommend that you take that walk to watch the process in action. You may discover some quirks that you would not have known had you not taken this step.