Entity Relationship Diagram (ERD)

An entity relationship diagram (ERD)_________.

• Is a use-case diagram enhanced graphically to show data and process modeling

• 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

• Is a graphical display of the processes in 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

• The expanded, thoroughly balanced and normalized use case for a system

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

On an ERD _________________:

• Processes are listed alphabetically with relationship connections drawn between processes

• Data elements are listed alphabetically with a cross listing to the processes that manipulate them

• Data elements are described as singular (1:1); plurals (1:N); or didactic (M:N)

• Data elements are grouped in a hierarchical structure that is uniquely identified by number

• Data elements are listed together and place inside boxes called entities

An entity ____________.

• Is the association between two related processes

• Has cardinality (1:1, 1:N, or M:N)

• Shows if it can be null or no null

• 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

• Home phone

• Gender

Lines on an ERD diagram indicate____________.

• Hierarchies between processes

• Relationships among the data

• Plurality of data items

• Uniqueness of data items

• Primary keys

The 4 major parts of an ERD diagram are___________.