MIS 3306 Test 1

Unary

A ___ relationship exists when an association is maintained within a single entity.

Ternary

A ____ relationship exists when three entities are associated.

Subtype discriminator

A ________ is the attribute in the supertype entity that determines to which entity subtype each supertype occurrence is related.

Record

A __________ is a logically connected set of one or more fields that describes a person, place, or thing.

Data dictionary

A ___________ contains at least all of the attribute names and characteristics for each table in the system..

Entity supertype

A ___________ is a generic entity type that is related to one or more entity subtypes.

Surrogate key

A ____________ is a primary key created by a database designer to simplify the identification of entity instances.

False

The SELECT operator yields a vertical subset of a table.

M:N

The entity relationship model uses the associative entity to represent a _________ relationship between two or more entities.

Optional

The existence of an ________ entity indicates that its minimum cardinality is zero.

Data redundancy

Which of the following refers to the situation where different versions of the same data are stored at different places because they weren't updated consistently?

Only one

Within a specialization hierarchy, every subtype can have ___ supertype to which it is directly related.

Foreign Key

A _________ is the primary key of one table that has been placed into another table to create a common attribute.

Simple

A_______ attribute is one that cannot be subdivided.

Primary

One important inheritance characteristic is that all entity subtypes inherit their ________ key attribute from their supertype.

True

RDBMSs enforce integrity rules automatically.

Integrity

Referential ________ dictates that the foreign key must contain values that match the primary key in the related table, or must contain null.

Subtype discriminator can be null

Which of the following is a specialization hierarchy disjoint constraint scenario in case of partial completeness?

Information

__________ is the result of revealing the meaning of raw facts.

Cardinality

_________expresses the minimum and maximum number of entity occurrences associated with one occurrence of the related entity.

Field

A ___________ is a character or group of characters that has specific meaning.

Entities

A relationship is an association between ____.

Weak

A________ entity has a primary key that is partially or totally derived from the parent entity in the relationship.

DBMS

A_________ is a collection of programs that manages the database structure and controls access to the data stored in the database.

1:1

At the implementation level, the supertype and its subtype(s) depicted in a specialization hierarchy maintain a(n) ____________ relationship.

False

Data anomaly is defined as the condition in which all of the database are consistent with the real-world events and conditions.

Column

Each table _________ represents an attribute.

True

Each table in a relational database must have a primary key.

Raw facts of interest to the end user

End-user data is _____.

Recursive

If an employee within an EMPLOYEE entity has a relationship with itself, that relationship is known as a _____ relationship.

Strong

If an entity can exist apart from all of its related entities, then it is existence-independent, and it is referred to as a ___________ entity.

Keys

In the relational model, ___________ are important because they are used to ensure that each row in a table is uniquely identifiable.

Enhanced entity relationship model

The extended entity relationship model (EERM) is sometimes referred to as the ___.

True

The only way to access the data in a database is through the DBMS.

False

The order of the rows and columns is important to the DBMS.

Inheritance

The property of ___________ enables an entity subtype to inherit the attributes and relationships of the supertype.

Cluster

The purpose of an entity _____________ is to simplify an entity-relationship diagram (ERD) and thus enhance its readability.

Database system

The term ________ refers to an organization of components that define and regulate the collection, storage, management and use of data within a database environment.

M:N

_____ relationships can be implemented by creating a new entity in 1:M relationships with the original entities.

Metadata

________ provide a description of the data characteristics and the set relationships that link the data found within the database.