chapter 3 - the relational database model

Question 1

In the relational model, an identifier is composed of one or more attributes that uniquely identifies a row.

Answer 1

primary key (PK)

Question 2

Any attribute in a specific row whose value directly determines other values in that row.

Answer 2

determinant

Question 3

A multiple-attribute key.

Answer 3

composite key

Question 4

An attribute that is part of a primary key.

Answer 4

key attribute

Question 5

An attribute or attributes that uniquely identify each entity in a table.

Answer 5

superkey

Question 6

A minimal superkey; that is, a key that does not contain a subset of attributes that is itself a superkey.

Answer 6

candidate key

Question 7

The property of a relational table that guarantees each entity has a unique value in a primary key and that the key has no null values.

Answer 7

Entity integrity

Question 8

The absence of an attribute value.

Answer 8

null

Question 9

An attribute or attributes in one table whose values must match the primary key in another table or whose values must be null.

Answer 9

foreign key

Question 10

A condition by which a dependent table’s foreign key must have either a null entry or a matching entry in the related table.

Answer 10

referential integrity