Lecture- Systems Development Lifecycle

Analysis & Design of Information Systems Systems Development Lifecycle (SDLC): Introduction Version 1.0 As a whole this lecture represents the term SDLC whose elaboration is Systems Development Lifecycle, we will undergo through all the phases. I will not discuss them in brief. In course of time, they will be represented. Why step by step systems development: When you develop a system, specially oriented with software, you need to go through some steps. Why steps? Well, let me tell you one thing- if you go through step by step, then if you lately think that something needs to be changed, you can easily switch to that step and change that. Moreover, for future works, if you want to figure out some mistakes in the current work and try not to let them occur again, you should have segment your current work, shouldn’t you? Then you can learn mistakes like- oh, I see, I made mistakes in step 3, 5 and 7- so be aware of them in the future works. Lifecycles of Systems development: Many definitions for SDLC, many steps in developing systems- you may become bruised if you see their differences. The main reason behind it is that there is no international standard for SDLC- follow this, follow that. But definitely some steps are always present in almost all the specifications. In this course, I will go through these steps. But remember, I am not saying that in the industry, you will have to follow the sequence here. But it is healthy to follow the sequence albeit. 1. Requirement analysis: Some systems experts suggest that this is the most important stage. You need to gather information from the user. The user is the king here. In reality, it will never happen that user wants a web application and you will build an animation for him. What really happens is you build the web application but there is only client side present, though user wanted an admin side as well. With some methodologies, we will cover how requirements are gathered. 2. Feasibility study: This phase calculates the feasibility of the system that the user defined. It may be a whole new system or maybe it is replacing an old system. This is a very crucial study. You need to take a look at the requirements and take into account some specific issues- will that do any good to developer and to user? If it is good, then this stage provides project plan and budgets. 3. Analysis: This is another important phase. In this phase, you need to analyze various aspects of later phases. i.e. you may say what if I make a recursive loop to solve a problem which is only 5 lines of coding, but time consuming than the linear coding which is 18 lines. You have to choose the better one and of course you have to do home works on them. 4. Design: Now, this is the last phase of logical part of SDLC. What you have analyzed, it is time to design them on paper with pen. In industry, it is usual to

Rushdi Shams

Dept of CSE, KUET

specify- for project X, there will be 3 functionalities- insert (12 modules), update (15 modules) and delete (11 modules). You have to design those modules, their interlinking with each other. The design should be perfect so that, if anything needs to be changed, you don’t have to bother about the whole coding of 210,000 lines. You should design it in a way so that you know for which bug, which lines are to be fixed. 5. Implementation: Nothing much folks, choose suitable language and develop the systems in that language. Just be aware of your coding style (I prefer structured coding) so that analysis and design phase are implemented physically and accurately. 6. Testing: When you are finished with coding, you need to test them. Loads of testing methodologies are out there. You may hear their names during the course- black box testing, white box testing, penetration testing, mutation testing, integration testing, volume testing, alpha testing, beta testing, blah blah blah! 7. Maintenance: In practical life, it is common to provide the user aftermathpost implementation maintenance. The user may ask- hey, how to install that, what to do with the interface, how can I connect to database with it- you know they are the king! You need to serve them. So be warned! Usually, this maintenance phase is limited- the king cannot be served by you more than particular time (say 30 days)!! Because, you have other customers to support! Some other important issues in Systems development: These are the main phases in SDLC. But if you want to add more, I did not mention 2 very important issues here- documentation and team meeting (maybe I forgot more). You can say we will have the documentation in the end- wrong!! You will have to keep up the documents as the systems get developed. But team meeting- that is your choice, you may say once in a month or once after each phase- I will not interfere with that one! Oh, feedback is one important thing. Every move you make, just make sure from the previous step specification- are you moving correctly? There are other components as well, you can say them sub components. These are the main parts. So, if you stay focus on these, you will discover the sub components as the course goes on, so don’t worry. Reading Materials: Start VB dot net SDLC.htm document: This tiny page should be read thoroughly. SDLC for small to medium database.pdf: You don’t have to go through the document meticulously. Just take a glimpse at the topics that I taught you today.

Rushdi Shams

Dept of CSE, KUET