24 Questions
What is the purpose of a report generator in a data-flow diagram?
To generate a report describing all named entities in the diagram
What is listed in a data dictionary?
All data elements appearing in the DFD model of a system
What is the significance of a data dictionary in software development?
It provides a means to determine the definition of various data structures
What does a data dictionary entry contain?
The objective and definition of the data item
What is the benefit of a data dictionary in a software development project?
It provides a standard language for all relevant information
What is the main purpose of a structured chart?
To partition a system into block boxes
What is the objective of the report generator?
To find all the names used in the data-flow diagram
What is contained in the data dictionary for the smallest units of data elements?
The name and type of the data item
What is the primary purpose of a Structured Chart?
To show the system partitions into modules
What is the main difference between pseudo-code and programming languages?
Pseudo-code avoids variable declaration
What does an Entity-Relationship model represent?
The relationship between entities and their attributes
What is the purpose of a Data Flow Diagram?
To show the flow of data through a system
What is a characteristic of a Black box system?
The user has no knowledge of the internal design
What is the main purpose of a Data Dictionary?
To define the attributes and their domains
What is the primary advantage of using pseudo-code?
It provides a method to perform a task
What is the purpose of a Structured Chart in software design?
To represent the system's functionality and its internal design
What is the term used to describe the logical association among entities?
Relationship
What type of mapping cardinality is used to describe a situation where one entity is associated with multiple other entities?
One to many
In object-oriented design, what is the term used to describe the distribution of state among objects?
Encapsulation
What is the term used to describe a group of similar objects in object-oriented design?
Class
What is the purpose of message passing in object-oriented design?
To enable objects to communicate with each other
What is the term used to describe the complexity handling technique in object-oriented design?
Abstraction
What is the term used to describe a procedure or function call in object-oriented design?
Message
What is the term used to describe the instance of a class in object-oriented design?
Object
Study Notes
Data-Flow Diagram Entities
- Data-flow diagram entities use different icons to represent data-flow diagrams, but their meanings are similar
- A report generator produces a report that describes all named entities in a data-flow diagram
- The report generator finds names used in the data-flow diagram, looks up a data dictionary, and retrieves information about each name
Data Dictionaries
- A data dictionary lists all data elements appearing in a Data-Flow Diagram (DFD) model of a system
- It contains data flows, contents of data stores, objectives of data items, and definitions of composite data elements
- Each data dictionary entry lists the name, type, and definition of data elements
- A data dictionary provides a standard language for engineers working on a project, ensuring consistent vocabulary for data items
- It helps determine definitions of data structures in terms of their component elements
Structured Charts
- A structured chart partitions a system into block boxes, showing:
- System partitions into modules
- Hierarchy of component modules
- Relations between processing modules
- Interaction between modules
- Information passed between modules
- Structured charts use specific notations to represent these concepts
Pseudo-Code
- Pseudo-code is written in a programming language style, with comments and descriptions
- It avoids variable declarations, using actual programming language constructs (e.g., C, Fortran, Pascal)
- Pseudo-code provides a method to perform a task, as if a computer is executing the code
- It contains more programming details than Structured English
Entity-Relationship Model
- Entity-Relationship (ER) model is a type of database model based on real-world entities and relationships
- ER Model creates a set of entities with attributes, constraints, and relations
- An entity is a real-world being with properties (attributes) and a set of values (domain)
- Relationships among entities are mapped with entities in various ways, with mapping cardinalities (one-to-one, one-to-many, many-to-one, many-to-many)
Object-Oriented Design
- In object-oriented design, a system is viewed as a collection of objects (entities)
- Each object handles its state data, and tasks defined for one object cannot refer or change data of other objects
- Objects are instances of a class, and classes may inherit features from a superclass
- Key terms in object-oriented design include:
- Objects: entities involved in the solution design
- Classes: generalized descriptions of objects
- Messages: objects communicate by message passing
This quiz covers the symbols and notation used in data-flow diagrams, including report generators and data dictionaries.
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