CHAPTER 2 Flashcards
The intent of a business rule is to break down business structure.
False
The total quiz points for a student for an entire semester is a(n) ________ attribute.
derived
A relationship instance is an association between entity instances where each relationship instance includes exactly one entity from each participating entity type.
False
A good data definition will describe all of the characteristics of a data object EXCEPT:
who can delete the data.
Enforcement of business rules can be automated through the use of software that can interpret the rules and enforce them.
True
The E-R model is used to construct a conceptual model.
True
A simple attribute can be broken down into smaller pieces.
False
It is not permissible to associate attributes with relationships.
False
In an E-R diagram, there are/is ________ business rule(s) for every relationship.
Two
Data modeling is about documenting rules and policies of an organization that govern data.
True
A ________ specifies the number of instances of one entity that can be associated with each instance of another entity.
cardinality constraint
A(n) ________ is the relationship between a weak entity type and its owner.
identifying relationship
Customers, cars, and parts are examples of:
entities.
The name used for an entity type should never be the same in other E-R diagrams on which the entity appears.
False
In an E-R diagram, strong entities are represented by double-walled rectangles.
False
A mutually exclusive relationship is one in which:
an entity instance can participate in only one of several alternative relationships.
Data modeling may be the most important part of the systems development process because:
data characteristics are important in the design of programs and other systems components.
An attribute that must be present for every entity (or relationship) instance is a(n):
required attribute.
Which of the following criteria should be considered when selecting an identifier?
Choose an identifier that doesn’t have large composite attributes.
In an E-R diagram, strong entities are represented by double-walled rectangles.
False- Weak Entity
The relationship between the instances of two entity types is called a binary relationship.
True
Some examples of attributes are: eye_color, weight, student_id, STUDENT.
False
Enforcement of business rules can be automated through the use of software that can interpret the rules and enforce them.
True
A ________ defines or constrains some aspect of the business.
business rule
A multivalued attribute may take on more than one value for a particular entity instance.
True
A customer can order many items, and an item can be ordered by many customers is an example of a recursive relationship.
True
Most systems developers believe that data modeling is the least important part of the systems development process.
False
The total quiz points for a student for an entire semester is a(n) ________ attribute.
derived
A simultaneous relationship among the instances of three entity types is called a ________ relationship.
ternary
A relationship between the instances of a single entity type is called a ________ relationship.
unary
Data names do not have to be unique.
False
One reason to use an associative entity is if the associative entity has one or more attributes in addition to the identifier.
True
A business rule is a statement of how a policy is enforced or conducted.
False
Relationships represent action being taken using a verb phrase.
True
A single occurrence of an entity type is called an entity instance.
True
The purpose of data modeling is to document business rules about processes.
False
The logical representation of an organization’s data is called a(n):
entity-relationship model.
A value that indicates the date or time of a data value is called a:
time stamp
Which of the following is an entity that exists independently of other entity types?
Strong
A simple attribute can be broken down into smaller pieces.
False
In an E-R diagram, an associative entity is represented by a rounded rectangle.
True
The relationship between a weak entity type and its owner is an identifying relationship.
True
A relationship instance is an association between entity instances where each relationship instance includes exactly one entity from each participating entity type.
False
Business rules are formulated from a collection of business ramblings.
False
The number of entity types that participate in a Unary relationship is:
one
The total quiz points for a student for an entire semester is a(n) ________ attribute.
derived
Customers, cars, and parts are examples of:
entities
The E-R model is used to construct a conceptual model.
True
A customer can order many items, and an item can be ordered by many customers is an example of a recursive relationship.
False
The logical representation of an organization’s data is called a(n):
entity-relationship model.
A relationship between the instances of a single entity type is called a ________ relationship.
unary
An attribute whose values can be calculated from related attribute values is called a derived attribute.
True
An entity type name should be all of the following EXCEPT:
as short as possible
Which of the following is NOT a good characteristic of a data name?
Relates to a technical characteristic of the system
A relationship where the minimum and maximum cardinality are both one is a(n) ________ relationship.
mandatory one
When choosing an identifier, choose one that will not change its value often.
True
A good data definition is always accompanied by diagrams, such as the entity-relationship diagram.
True
