CHAPTER 5 REVIEWData and Process Modeling

Question 1

Describe data and process modeling, and name the main data and process modeling techniques.

Question 1

Describe data and process modeling, and name the main data and process modeling techniques.

Four-Model Approach – develops a physical model of the current system, a logical model of the current system, a logical model of the new system, and a physical model of the new system.

Question 2

Explain the purpose of a data flow diagram. Name and draw the four symbols using the Gane and Sarson and the Yourdon styles.

Question 2

Explain the purpose of a data flow diagram. Name and draw the four symbols using the Gane and Sarson and the Yourdon styles.

Question 3

Define process and give four examples of typical process names.

Question 3

Define process and give four examples of typical process names.

Process = procedure or task that users, managers, and IT staff members perform – the logical rules of a system that are applied to transform data into meaningful information. In DFD Data Flow Diagrams, a process receives input data and produces output that has a different content, form or both.

Example … pay rate TIMES hours worked PRODUCES output of total pay.

Question 4

Define data flow and give four examples of typical data flow names

Question 4

Define data flow and give four examples of typical data flow namesData Flow = path for data to move from one part of the information system to another Examples of “data flow names”OrderInvoicePaymentCommissionDepositStudent Grade

Question 5

Define data store and give four examples of typical data store names.

Question 5

Define data store and give four examples of typical data store names.

Data Store = data repository = a situation in which a system must retain data for later use by a process Examples of “data store names” StudentsEmployeesProducts

Question 6

Define external entity and give four examples of typical external entity names.

Question 6

Define external entity and give four examples of typical external entity names.

External Entity = objects outside the system being modeled, and interact with process in system

Question 7

What is a context diagram? What symbol is not used in a context diagram?

Question 7

What is a context diagram? What symbol is not used in a context diagram?

Context diagram = a top-level view of an information system that shows the boundaries and scope

Question 7

What is a context diagram? What symbol is not used in a context diagram?

The Symbol NOT USED is the Letter “O”

Question 8

What is the relationship between a context diagram and a diagram 0? Briefly describe each. How are they alike? How are they different?

Question 8

What is the relationship between a context diagram and a diagram 0? Briefly describe each. How are they alike? How are they different?Context Diagram offers a simpler structure how a Process flows to Data Stores and External Entities.

At top level, it centers on one process – labeled as Zero with data flow lines to and from key External Entities. 

Question 8

What is the relationship between a context diagram and a diagram 0? Briefly describe each. How are they alike? How are they different?Diagram 0 details show a Process exploded to other Processes with flow lines to and from Data Stores and External Entities. As an explosion showing the Context Diagram Process Zero, this one process is not individually listed, but instead the next level of process One and other Natural Number processes are listed.

Question 8

What is the relationship between a context diagram and a diagram 0? Briefly describe each. How are they alike? How are they different?Diagram 0 gives a first level of detail on the initial Context Diagram, zooming in on the Context Diagram and showing major processes, data flows and data stores, as well as repeating the external entities and data flows that appear in the Context Diagram.

Question 8

What is the relationship between a context diagram and a diagram 0? Briefly describe each. How are they alike? How are they different?Similarities = both include how Data Flow Lines connect External Entity to Central Process. Each have a header identity number for a Process. Differences = A more complex Diagram 0 can include Data Stores, yet the simpler Context Diagram does not. A primary Context Diagram has one Process identified with header 0. The exploded Diagram 0 has one or more Processes identified with headers of 1 and other Natural Numbers.

Question 9

What is a balanced data flow diagram?

Question 9

What is a balanced data flow diagram?

Balanced Data Flow Diagram = when a primitive parent process is exploded to demonstrate further detail in a child diagram, balance exists if the child has the same input and output flows as the parent process.

Question 10

Name 8 rules or conventions of data flow diagrams.

Question 10

Name 8 rules or conventions of data flow diagrams.• Draw the Context Diagram within one page• Do not cross lines• Any processes in any level diagram has a unique-name

and unique reference-number• Every data element must be documented in the data

dictionary.• Data Flows must begin, end, or both begin & end with a

process • Data Stores cannot create (or destroy) any data. A

process gets data into a data store.• Processes cannot create data out of thin air, but

manipulate data received from data flows

Question 11

Explain the DFD leveling technique.

Question 11

Explain the DFD leveling technique.

Leveling = process of drawing a series of increasingly detailed diagrams to reach the desired level of detail, where all functional primitives are identified

This exploding, partitioning, or decomposing expounds the operation of every process within any process

Question 12

Where do you document the details of data flows, data stores, and processes?

Question 12

Where do you document the details of data flows, data stores, and processes?

A data dictionary, or data repository, is a central storehouse of information about the system’s data.

Every data element gains documentation, definition, description in the data dictionary. All data flows, data stores, and processes gain documentation in the data dictionary.

Question 13

What is a functional primitive?

Question 13

What is a functional primitive?

Functional Primitive = a process that consists of a single function that is not exploded further. The logic is documented in a data dictionary process description.

Question 14

Define the following terms: black hole, decompose, spontaneous

generation

Question 14

Define the following terms: black hole, decompose, spontaneous

generationBlack Hole = a process that has no output  Decompose = Another way to convey a process or system that has been broken down from a top-level, general view into more detail – partitioning  Spontaneous Generation = an unexplained generation of data or information. Within DFDs, processes cannot spontaneously generate data flows, they must receive input to provide

Question 15

Given the following scenario, draw either a decision table or decision tree.The FVTC course catalog indicates that to enroll in 107-158 (Systems Analysis and Design) a student must have completed 107-100 (Computer Concepts and Careers) and 107-150 (Microcomputer Applications). A student who completes either one of the prerequisites and obtains the instructor’s permission, however, will be allowed to take Systems Analysis and Design.

Question 15

Given the following scenario, draw either a decision table or decision tree.