Jamia polytechnic institute 2.pptx irririd

Hi am study diploma in Computer engineering and technology and

1. Jamia polytechnic institute

2. Group Member 1.Sayyed Mannan 2.Mohammad M aaz 3. S ayed H ammad 4. S ayed F aizan

3. Data flow diagram DFD  is the abbreviation for  Data Flow Diagram . The flow of data of a system or a process is represented by DFD. It also gives insight into the inputs and outputs of each entity and the process itself. DFD does not have control flow and no loops or decision rules are present. Specific operations depending on the type of data can be explained by a flowchart. It is a graphical tool, useful for communicating with users ,managers and other personnel. it is useful for analyzing existing as well as proposed system.

4. Data flow diagram

5. Characteristics of Data Flow diagram Characteristics Information and/or data flow is represented by a labeled arrow Processes (transformations) are represented by labeled circles (bubbles) Information sources and sinks are represented by boxes Files and depositories are represented by a rounded rectangle or a double line.

6. Types of data flow diagram Context Diagram Level 0 DFD Lower level DFDs Logical DFD Physical DFD

7. Level 0 DFD

8. Lower level DFDs

9. Advantage of data flow diagram i t aids in describing the boundaries of the system. It is beneficial for communicating existing system knowledge to the users. A straightforward graphical technique which is easy to  recognise . DFDs can provide a detailed representation of system components. It is used as the part of system documentation file. DFDs are easier to understand by technical and nontechnical audiences It supports the logic behind the data flow within the system.

10. disadvantage of data flow diagram It make the programmers little confusing concerning the system . The biggest drawback of the DFD is that it simply takes a long time to create, so long that the analyst may not receive support from management to complete it. Physical considerations are left out.