Database Systems and Data Modeling: Key Concepts and Relationships
The SDLC phase in which the detailed conceptual data model is created is the _______ phase.
Analysis
An attribute that can be broken down into smaller parts is called a(n) _______ attribute.
Composite
A primary key that consists of more than one attribute is called a:
Composite key
_______ is a component of the relational data model included to specify business rules to maintain the integrity of data when manipulated.
Data integrity
Customers, cars, and parts are examples of:
Entities
A person, place, object, event, or concept about which the organization wishes to maintain data is called a(n):
Entity
The logical representation of an organization's data is called a(n):
Entity-relationship model
The process of defining a more general entity type from a set of more specialized entity types is called:
Generalization
_______ are established between entities in a well-structured database so that desired information can be retrieved.
Relationships
Subtypes should be used when:
There are attributes that apply to some but not all instances of an entity type
If an identifier is not assigned, the default primary key for an associative relation consists of the two primary key attributes from the other two relations.
True
Information is processed data.
True
Metadata are data that describe the properties of other data.
True
One property of a relation is that each attribute within a relation has a unique name.
True
Redundancy increases the risk of inconsistent data.
True
The overlap rule specifies that if an entity instance of the supertype is a member of one subtype, it can simultaneously be a member of two (or more) subtypes.
True
The systems development life cycle is the traditional methodology used to develop, maintain, and replace information systems.
True
In the VEHICLE diagram, CAR and TRUCK are generalized to which entity?
Vehicle
When transforming a one-to-one relationship, a new relation is always created.
False
With the traditional file processing approach, each application shares data files, thus enabling much data sharing.
False
All of the following are properties of metadata EXCEPT:
Processing logic
An entity that associates instances of entity types and contains attributes specific to the relationships is called a(n):
Associative entity
A property or characteristic of an entity type that is of interest to the organization is called a(n):
Attribute
A _______ defines or constrains some aspect of the business.
Business rule
A _______ specifies the number of instances of one entity that can be associated with each instance of another entity.
Cardinality constraint
Question
Correct Answer
Data modeling may be the most important part of systems development because:
Data characteristics are important in the design of programs and systems components
Program-data dependence is caused by:
Data descriptions being written into programming code
Which organizational function should set database standards?
Database Administration
Which software is used to create, maintain, and provide controlled access to databases?
Database management system (DBMS)
The number of entity types that participate in a relationship is called the:
Degree
An attribute that can be calculated from related attribute values is called a _______ attribute.
Derived
The PATIENT diagram with 'd' shows a patient must be either outpatient OR resident. This is the _______ rule.
Disjoint
The _______ rule specifies that an entity can be a member of only one subtype at a time.
Disjoint
Database development begins with _______, which establishes the range and general contents of organizational databases.
Enterprise data modeling
A composite key consists of only one attribute.
False
A member of a subtype does NOT necessarily have to be a member of the supertype.
False
A subtype is a generic entity that has a relationship with one or more entities at a lower level.
False
A well-structured database establishes the entities between relationships in order to derive the desired information.
False
When all multivalued attributes have been removed from a relation, it is said to be in:
First normal form (1NF)
An attribute in a relation that serves as the primary key of another relation in the same database is called a:
Foreign key
The number of entity types that participate in a Unary relationship is:
One
A form of database specification which maps conceptual requirements is called:
Logical specifications
A database is an organized collection of _______ related data.
Logically
Business policies and rules govern all of the following EXCEPT:
Managing employees
A relationship where the minimum and maximum cardinality are both one is a(n) _______ relationship.
Mandatory one
A student can attend 5 classes, each with a different professor. Each professor has 30 students. The relationship of students to professors is a _______ relationship.
Many-to-many
All of the following are the main goals of normalization EXCEPT:
Maximize storage space
Data that describe the properties of other data are:
Metadata
The entity integrity rule states that:
No primary key attribute can be null
In the PATIENT diagram, which of the following is a subtype of PATIENT?
Outpatient
The _______ rule states that an entity instance can simultaneously be a member of two or more subtypes.
Overlap
The ROOM diagram with Y indicators on multiple subtypes is an example of the _______ rule.
Overlap rule
The subtype discriminator is a composite attribute when there is a(n):
Overlap rule
In the PART diagram, what is the subtype discriminator?
Part_Type
The _______ rule specifies that an entity instance of a supertype is allowed NOT to belong to any subtype.
Partial specialization
An attribute (or attributes) that uniquely identifies each row in a relation is called a:
Primary key
Which of the following is NOT an advantage of database systems?
Redundant data
A rule that states each foreign key value must match a primary key value in the other relation is called the:
Referential integrity constraint
Which of the following is NOT a good characteristic of a data name?
Relates to a technical characteristic of the system
An attribute that must have a value for every entity (or relationship) instance is a(n):
Required attribute
The process of defining one or more subtypes of a supertype and forming relationships is called:
Specialization
Which of the following is an entity that exists independently of other entity types?
Strong
An attribute of the supertype that determines the target subtype(s) is called the:
Subtype discriminator
Which of the following is a generic entity type that has a relationship with one or more subtypes?
Supertype
Data is represented in the form of:
Tables
A simultaneous relationship among instances of three entity types is called a _______ relationship.
Ternary
A cascading delete removes all records in other tables associated with the record to be deleted.
True
A data model is a graphical system used to capture the nature and relationships among data.
True
A modern DBMS automates more of the backup and recovery tasks than a file system.
True
A primary key is an attribute that uniquely identifies each row in a relation.
True
A referential integrity constraint is a rule that maintains consistency among the rows of two relations.
True
A subtype can become a supertype if the subtype has other subtypes beneath it.
True
A well-structured relation contains minimal redundancy and allows users to manipulate the relation without errors or inconsistencies.
True
An entity instance of a subtype represents the same entity instance of the supertype.
True
Data structures include data organized in the form of tables with rows and columns.
True
In an E-R diagram, there are/is _______ business rule(s) for every relationship.
Two
Because applications are often developed independently in file processing systems:
Unplanned duplicate data files are the rule rather than the exception
An entity type whose existence depends on another entity type is called a _______ entity.
Weak
A relation that contains minimal redundancy and allows easy use is considered to be:
Well-structured
