Exam 4: Entity Relationship (ER)Modeling

A derived attribute is indicated in the Chen model by a ____.

In the original ERM described by Chen,relationships do not contain ____________________.

In Chen notation,there is no way to represent cardinality.

____ attributes can have many values.

A composite identifier is a primary key composed of more than one attribute.

In Crow's Foot notation,an optional relationship between entities is shown by drawing a(n)____________________ on the side of the optional entity.

Cardinality expresses the minimum and maximum number of entity occurrences associated with one occurrence of the related entity.

In an ER diagram,primary keys are indicated by ____.

A(n)____________________ relationship is also known as an identifying relationship.

In an ER diagram,primary keys are usually bolded.

Some ____________________ database modeling concepts can be expressed only using the Chen notation.

The Crow's Foot model is less implementation-oriented than the Chen model.

The ERD represents the ____ database as viewed by the end user.

A(n)____________________ attribute need not be physically stored within the database.

Connectivities and cardinalities are usually based on ____________________ rules.

Attributes cannot share a domain.

A(n)____________________ relationship exists when two entities are associated.

Knowing the ____ number of entity occurrences is very helpful at the application software level.

In both the Chen and Crow's Foot models,an entity is represented with a rectangle containing the entity's name.

What is a ternary relationship? Provide some example business rules that specify the need for a ternary or higher-order relationship.