9. What is the difference between a logical and physical data flow diagram? A logically-oriented data flow diagram shows how the business operates. A physically-oriented data flow diagram shows how the system will be implemented using technology and manual procedures.
What are common features of logical DFD and physical DFD?
Summary Logical vs Physical DFD
| Features | Logical | Physical |
|---|---|---|
| Data store | Collections of data | Physical files and databases, manual files |
| Type of data store | Permanent data collections | Master files, transaction files |
| System controls | Business controls | Controls for data validation, record status, system security |
What is the difference between DFD and activity diagram?
In data flow diagrams, the lines between “boxes” represent data that flows between components of a system. Because these only show the flow of data, they do not give an indication of sequencing. In activity diagrams, those lines are simply transitions between activities and do not represent data flow at all.
When would you use the logical data flow and when would you use the physical data flow?
Logical DFD is used in various organizations for the smooth running of system. Like in a Banking software system, it is used to describe how data is moved from one entity to another. Physical DFD: Physical data flow diagram shows how the data flow is actually implemented in the system.
Which type of data flow diagram specifies where how and by whom a system’s processes are performed?
An external entity is a person, place, or thing within the system that transforms data. ANS: F PTS: 1 22. A physical data flow diagram (DFD) uses bubbles to specify where, how, and by whom a system’s processes are accomplished. ANS: T PTS: 1 23.
What are the four data items that can be symbolized on a data flow diagram?
All data flow diagrams include four main elements: entity, process, data store and data flow.
What is the meaning of physical logical?
Logical implies a higher view than the physical. Users relate to data logically by data element name; however, the actual fields of data are physically located in sectors on a disk. For example, to find out which customers ordered how many of a particular product, the logical view is customer name and quantity.
What is a logical diagram in philosophy?
“Logic diagrams” are geometrical figures that are in some respect isomorphic with the structure of statements in a formal logic and therefore can be manipulated to solve problems in that logic.
What is the main difference between an activity and sequence diagram?
Activity and sequence diagrams are two behavior diagrams. The main difference between activity diagram and sequence diagram is that the activity diagram represents the flow of activities in a system while the sequence diagram represents the sequence of messages flowing from one object to another.
What is the difference between class diagram and use case diagram?
UML Use case diagrams represent the “requirements” of the system. Class diagrams show the building blocks (classes) that are needed to build the software/system. They are the software entities that are used to build the system and their relationships.
Which symbol is not used in a context diagram?
Which symbol is not used in a context diagram? The context diagram provides different views of information system. Diagram 0 is used to provide insight view of an info system represents internal process, entities, data flow, and data storage. Data stores are not used in a context diagram.
What is a logical DFD?
The logical DFD describes what the system does by including the essential sequence of business activities. It model the business data and activities instead of actual forms, location and roles. The example below shows a logical DFD and a physical DFD for a grocery store cashier:
What is a physical DFD and why is it important?
A physical DFD can depict a current system or show how a new system will be implemented. The processes shown represent programs, program modules and manual procedures, while the data stores shown represent databases and manual files. The physical DFD also shows system controls for:
What is the difference between logical and physical data flow diagram?
So while any data flow diagram maps out the flow of information for a process or system, the logical diagram provides the “what” and the physical provides the “how.”. They are two different perspectives on the same data flow, each designed to visualize and improve the system. The logical DFD describes the business events
What is physical DFD in Linux?
Physical DFD depicts how the system will be implemented (or how the current system operates). The processes represent the programs, program modules, and manual procedures. The data stores represent the physical files and databases, manual files.
