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Sunday, May 6, 2007

Week 9


Traditional design,
Design phase can be in two ways; traditional & OO the design you choose is in close collaboration with the analysis but doesn't mean if you have done OO analysis you can't move to traditional design. yet some parts don't match...
Traditional approach focuses on top-down approach decomposition of function to be performed by given program. what the user see when interacts with system is user interface, behind that interface thousands of programing code exists.
Consider system analysis & design book, it has many chapter & each chapter talks about one topic, on the other hand to understand some chapters you have to read previous chapters... this is exactly what happens in traditional design, the application software (the book) is divided into many modules (like chapters) and each module should perform one specific function which is referred to as cohesion, the more the function is specific & identifiable the more module is cohesive (highly cohesive). modules are connected to each other but what we are looking for is not strong relationship between modules. modules which are not heavily connected to each other are called loosely coupled. modules with high cohesiveness & less coupling are desired since codes are easy to find & locate and changing one module doesn't lead to chaos.
The models we use to represent traditional approach can be divided into 3 type: flowchart, structure chart & pseudo code.

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