CISD40-7

"What are ""business rules"" and what is their role in database design? "

"business rules"" is a brief, precise, and unambiguous description of a policy, procedure, or principle within a specific organization. In database design, they help to standardize the company's view of data. They can be communications tool between users and designers. They allow the designer to understand business processes. They allow the designer to develop appropriate relationship participation rules and constrains and to create an accurate data mode."

An ID-dependent entity is:

Both a special type of weak entity and an entity in which the identifier of the entity includes the identifier of another entity

Maximum cardinality indicates whether or not an instance of one entity class must be related to at least one instance of another entity class.

F

One type of strong entity is the ID-dependent entity.

F

The PRODUCT entity instance is the collection of all PRODUCT entity classes.

F

The number of entity classes involved in a relationship is the cardinality of the relationship.

F

There is usually only one instance of an entity in an entity class.

F

Unified Modeling Language (UML) has quickly replaced the E-R Model as the most popular technique for creating data models.

F

An entity class is described by the structure of the entities in that class.

T

An entity identifier can be either unique or nonunique.

T

E-R Model assumes that all instances of a given entity class have the same attributes.

T

It is possible for an entity to have a relationship to itself.

T

Use cases can be used to validate the data model, design, and implementation.

T

Which of the following is true about identifiers of entities?

The value of an identifier may identify a set of entity instances.

Which of the following is not a basic element of the E-R Model?

Use cases

A dashed line between entities indicates:

a nonidentifying relationship.

The number of entity classes involved in a relationship is known as the relationship's:

degree

In the Entity-Relationship data model, all instances of an entity of a given type are grouped into:

entity classes.

Whether or not an instance of one entity class must participate in a relationship with another entity class is indicated by the:

minimum cardinality