Modern Database Management - Self Check 02

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A ________ specifies the number of instances of one entity that can be associated with each instance of another entity.

cardinality constraint

A logical representation of the data for an organization or for a business area is called a(n) ________.

entity-relationship model

A ________ is an association between two or more terms.

fact

A single occurrence of an entity type is called an entity ________.

instance

A ________ may be associated with any data value that changes over time when we need to maintain a history of those data values.

time stamp

In an E-R Diagram, strong entities are represented by double-walled rectangles.

F

In the figure below, one might want to create a single-attribute surrogate identifier to substitute for the composite identifier.

F

In the figure below, the name of the relationship follows the guidelines for naming a relationship.

F

The maximum criminality of a relationship is the maximum number of instances of entity B that may be associated with each instance of entity A.

F

The name used for an entity type should never be the same in other E-R diagrams on which the entity appears.

F

The purpose of data modeling is to document business rules about processes.

F

The relationship among the instances of three entity types is called a unary relationship.

F

When systems are automatically generated and maintained, quality is diminished.

F

An attribute whose values can be calculated from related attribute values is called a derived attribute.

T

An entity is a person, place, object, event, or concept in the user environment about which the organization wishes to maintain data.

T

The relationship between the instances of two entity types is called a binary relationship.

T

When choosing an identifier, choose one that will not change its value often.

T

While business rules are not redundant, a business rule can refer to another business rule.

T

An identifier should be chosen that has valid values and is not ________.

null

A simultaneous relationship among the instances of three entity types is called a ________ relationship.

ternary

A ________ relationship occurs between two instances of a single entity type.

unary

A relationship name is a ________.

verb phrase

A business rule is a statement of how a policy is enforced or conducted

F

A cardinality constraint tells what kinds of properties are associated with an entity.

F

A relationship instance is an association between entity instances where each relationship instance includes exactly one entity from each participating entity type.

F

A simple attribute can be broken down into smaller pieces.

F

Data names do not have to be unique.

F

An entity type that associates the instances of one or more entity types and contains attributes that are peculiar to the relationship is called a(n) ________.

associative entity

A property or characteristic of an entity is a(n) ________.

attribute

A ________ is a statement that defines or constrains some aspect of the business.

business rule

A ternary relationship is equivalent to three binary relationships.

F

An affirmative entity is also called a relationship entity.

F

An entity type on which a strong entity is dependent is called a covariant entity.

F

An example of a term would be the following sentence: "A student registers for a course."

F

Business rules are formulated from a collection of business ramblings.

F

It is not permissible to associate attributes with relationships.

F

Most systems developers believe that data modeling is the least important part of the systems development process.

F

Some examples of attributes are: eye_color, weight, student_id, student.

F

The degree of a relationship is the number of attributes that are associated with it.

F

The intent of a business rule is to break down business structure.

F

A business rule is a statement that defines or constrains some aspect of the business.

T

A business rule should be internally consistent.

T

A fact is an association between two or more terms.

T

A good data definition is always accompanied by diagrams, such as the entity-relationship diagram

T

A multivalued attribute may take on more than one value for a particular entity instance.

T

A single occurrence of an entity is called an entity instance.

T

A time stamp is a time value that is associated with a data value.

T

An entity type name should always be a singular noun.

T

Data names should always relate to business characteristics.

T

Data rather than processes are the most complex aspects of many modern information systems

T

Enforcement of business rules can be automated through the use of software tools that can interpret the rules and enforce them.

T

In an E-R Diagram, an associative entity is represented by a rounded rectangle.

T

It is desirable that no two attributes across all entity types have the same name.

T

One of the roles of a database analyst is to identify and understand rules that govern data.

T

One reason to use an associative entity is if the associative entity has one or more attributes in addition to the identifier.

T

Participation in a relationship may be optional or mandatory.

T

Relationships represent action being taken using a verb phrase.

T

The E-R model is used to construct a conceptual model.

T

The relationship between a weak entity type and its owner is an identifying relationship.

T

An attribute that can be broken down into component parts is called a(n) ________ attribute.

composite

The number of entity types that participate in a relationship is called the ________ of the relationship.

degree

An attribute whose value can be calculated from a related attribute is called a(n) ________ attribute.

derived

A(n) ________ is an attribute that uniquely identifies individual instances of an entity type.

identifier

A weak entity type is related to its owner by a(n) ________

identify relationship

A meaningful relationship between entity types is called a(n) ________.

relationship type

An entity-type name should be ________ to the organization.

specific

A(n) ________ entity type exists independently of other entity types.

strong


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