Database Management 6

Question 1

is a key that is composed of more than one attribute. An attribute that is a part of a key is called a key attribute.

Answer 1

composite key

Question 2

is a key that can uniquely identify any row in the table. In other words, a ??? functionally determines every attribute in the row.

Answer 2

superkey

Question 3

is a minimal superkey—that is, a superkey without any unnecessary attributes.

Answer 3

A candidate key

Question 4

is the condition in which each row (entity instance) in the table has its own unique identity. To ensure entity integrity, the primary key has two requirements: (1) all of the values in the primary key must be unique, and (2) no key attribute in the primary key can contain a null.

Answer 4

Entity integrity

Question 5

is the absence of any data value, and it is never allowed in any part of the primary key.

Answer 5

null

Question 6

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

Answer 6

foreign key (FK)

Question 7

the condition in which every reference to an entity instance by another entity instance is valid.

Answer 7

referential integrity

Question 8

is defined as a key that is used strictly for data retrieval purposes. A secondary key’s effectiveness in narrowing down a search depends on how restrictive the key is.

Answer 8

secondary key

Question 9

This rule states that if an attempt is made to delete a record in one table where one or more records with matching foreign key values exist in another table, all associated records will be deleted.

Answer 9

Cascade Delete Rule

Question 10

This rule states that if an attempt is made to delete a record in one table where one or more records with matching foreign key values exist in another table, that the delete operation will not be allowed.

Answer 10

Restrict Delete Rule