Data Dictionary and Element Attributes

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Questions and Answers

What is the primary function of a data flow in a data flow diagram (DFD)?

To represent the processing of data

To define the endpoints of a data sequence

To indicate the storage of data

To show the movement of data between parts of an information system (correct)

Which symbol is used to represent a data flow in a DFD?

An oval

A line with a single or double arrowhead (correct)

A rectangle

A circle

What should the name of a data flow include?

A verb and a noun

Only a proper noun

A numeric value

A singular noun and an adjective if necessary (correct)

In the context of a DFD, which of the following is NOT a correct representation of data flow?

A line without an arrow Signup and view all the answers

How many data flow symbols are explicitly identified in the provided content?

None specified Signup and view all the answers

What is the primary purpose of a data flow diagram?

To illustrate how data moves through an information system Signup and view all the answers

Which of the following is NOT a basic symbol used in data flow diagrams?

User interface Signup and view all the answers

What do process symbols in a data flow diagram represent?

Processes that transform data Signup and view all the answers

Which naming convention is used for process names in data flow diagrams?

A verb followed by a singular noun Signup and view all the answers

How does the DFD treat the underlying logic of processes?

It does not focus on underlying logic, treating processes as black boxes Signup and view all the answers

Which set of symbols is commonly used in the examples provided in the related material?

Gane and Sarson symbols Signup and view all the answers

Why might a data flow diagram be described as a logical model?

It focuses on what the system does rather than how it does it Signup and view all the answers

What is the function of entities in a data flow diagram?

To represent external agents that interact with the system Signup and view all the answers

What shape is used to represent a data store in a DFD according to the Gane and Sarson symbol?

Flat rectangle open on the right side Signup and view all the answers

Which of the following is a characteristic of a data store name in a DFD?

It consists of a plural noun and adjectives. Signup and view all the answers

What type of entities are shown in a Data Flow Diagram (DFD)?

External entities that provide or receive data Signup and view all the answers

How must a data store be connected within a Data Flow Diagram?

It must be connected to a process with a data flow. Signup and view all the answers

What is the purpose of an entity in a Data Flow Diagram?

To serve as data origins or final destinations Signup and view all the answers

What feature might be used to visually distinguish an entity in a DFD?

A shaded rectangle Signup and view all the answers

What term is used for an entity that supplies data to the system?

Source Signup and view all the answers

What symbol is incorrect for representing a data store in a DFD?

Flat rectangle closed on both sides Signup and view all the answers

What is the primary purpose of a data dictionary?

To provide clear and comprehensive information about data and processes Signup and view all the answers

Which of the following is NOT typically included as an attribute in a data element description?

User access level Signup and view all the answers

Which attribute is essential for documenting a data flow in the data dictionary?

Data flow name or label Signup and view all the answers

What aspect of a data store is typically documented within a data dictionary?

Description and alternate names Signup and view all the answers

Which of the following attributes is crucial for understanding the frequency of data flows?

Volume Signup and view all the answers

The term 'metadata' in the context of a data dictionary refers to what?

Information about other data Signup and view all the answers

Which characteristic of a data element indicates its allowable values?

Acceptable values Signup and view all the answers

What documentation is necessary for every data element in a data dictionary?

Comprehensive data descriptions Signup and view all the answers

What does a logical model represent in system design?

What the system must do, independent of implementation Signup and view all the answers

Which statement correctly describes the transition from a logical model to a physical model?

The logical model's requirements inform the construction of the physical model. Signup and view all the answers

What is a primary characteristic of a physical model in system design?

It specifies how the system components will be implemented. Signup and view all the answers

Why is it important to differentiate between logical and physical models?

Each model serves a separate purpose in the design process. Signup and view all the answers

What outcome is expected after establishing the logical model?

Development of the physical model based on approved specifications Signup and view all the answers

What is an incorrect assumption about logical models?

They are only concerned with implementation details. Signup and view all the answers

How do logical and physical models interact during the systems design phase?

The logical model provides a framework that influences the physical model. Signup and view all the answers

Which of the following is a fundamental difference between logical and physical models?

Logical models detail system behavior, while physical models address implementation. Signup and view all the answers

Study Notes

Data Dictionary

Contains information about data, including its meaning, relationships to other data, origin, usage, and format
Includes data element descriptions, attribute/property definitions, relationship descriptions, rules and constraints, and other metadata

### Data Element Attributes

Data element name, alias, type and length, default value, acceptable values, source, security, responsible user(s), and description/comments are documented
The objective is to provide clear, comprehensive information about the data and processes that make up a system

Data Flows

All data flows in the data dictionary must be documented
Typical attributes include data flow name or label, description, alternate name(s), origin, destination, record, volume, and frequency

### Data Stores

Every DFD data store in the data dictionary must be documented
Typical characteristics of a data store include data store name or label, description, alternate name(s), attributes, and volume and frequency

Data Flow Diagrams (DFDs)

Use various symbols to show how the system transforms input data into useful information
Show how data moves through an information system but do not show program logic or processing steps
A logical model that shows what the system does, not how it does it

Data Flow Diagram Symbols

Use four basic symbols representing processes, data flows, data stores, and entities
Several versions of DFD symbols exist (Gane and Sarson symbols are used in the textbook, Yourdon symbols are another popular set)

Process Symbols

Contain business logic which transform data and produce the required results
The process name on the symbol identifies a function consisting of a verb followed by a singular noun (e.g.: APPLY RENT PAYMENT)
A process symbol can be called a black box because the process’s inputs, outputs, and functions are known, but underlying logic is hidden

Data Flow Symbols

Represents one or more data items
Symbol is a line with a single or double arrowhead
Data flow name includes a singular noun and an adjective (if needed)

Data Store Symbols

Represents data that the system stores because one or more processes need to use the data later
Symbol is a flat rectangle that is open on the right side and closed on the left
Data store name is a plural name consisting of a noun and adjectives (if needed)
Must be connected to a process with a data flow

Entity Symbols

Symbol is a rectangle, which may be shaded to make it look three-dimensional
Shows only external entities that provide data to the system or receive output from the system
Also called terminators because they are data origins or final destinations
An entity that supplies data to the system is called a source
An entity that receives data from the system is called a sink

Logical and Physical Models

A logical model shows what the system must do, regardless of how it will be implemented physically.
Later, in the systems design phase, a physical model is built that describes how the system will be constructed.

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Description

This quiz explores the fundamental concepts of data dictionaries, including data element attributes, data flows, and data stores. Participants will learn about the essential components that define data structures and how they relate to each other. Gain insight into metadata, data relationships, and the significance of clear documentation in data management.