Entity Relationship Diagram (ERD)

An entity relationship diagram (ERD)_________.

• Is a graphical display of the processes in a business system

• Is a high-level CASE diagram of data modeling used in business systems

• Is an illustration of external data flows to and from a business systems

• Is a picture that shows the information that is created, stored, and used by a business system

A data model is a ______________.

• The mathematical model of formulas and logic used in a system

• The abstract creating of an ideal system transformation

• The model that is produced by extreme programming

• A formal way of representing the data that are used and created by a business system

An entity ____________.

• Is the association between two related processes

• Has cardinality (1:1, 1:N, or M:N)

• Is a person, place or thing

• Is described with a verb phrase

Which would NOT likely be an attribute of an entity called “Student”?

• Age

• Student identification number

• Class room number

• Gender

Lines on an ERD diagram indicate____________.

• Hierarchies between processes

• Relationships among the data

• Uniqueness of data items

• Primary keys

The ERD diagram cannot have

• Relationships

• Entities

• Database

• Attributes

Which of the follwing cannot be a multivalued attribute

• Degree

• Skill

• Division

• First_Name

Which of the following is a single entity instance of one type related to many instances of another type?

• one to one relationship

• one to many reatlionship

• Many to many relationship

• Composite relationship

In ER diagram rectangles are used to denote

• Attributes

• Entities

• Realtionships

• Relationships

In ER diagram derived attributes are denoted by

• Dotted triangle

• Dotted ovel

• Dotted rectangle

• Dotted square