Modern Database Management - Self Check 02
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
