Tiêu đề Chapter03.pptx ✅

Chapter Objectives (1 of 2) By the end of this chapter, you should be able to: Describe the relationship between logical and physical models. Explain data flow diagrams. Draw the four basic data flow diagram symbols. Explain the six guidelines used when drawing data flow diagrams. Draw context diagrams.

Logical versus Physical Models A logical model shows what the system must do, regardless of how it will be implemented physically A physical model describes how the system will be constructed Many analysts follow a four-model approach which develops: A physical model of the current system A logical model of the current system A logical model of the new system A physical model of the new system