The Relational Model

Question 1

Domain

Answer 1

the set of allowable values for one or more attributes

Question 2

Instance

Answer 2

A tuple with values for each field

Question 3

Degree

Answer 3

Number of attributes it contains

Question 4

Cardinality

Answer 4

number of tuples it contains

Question 5

Relations schema

Answer 5

A named relation defined by a set of attribute and domain name pairs.

Question 6

Superkey

Answer 6

An attribute or set of attributes that uniquely identifies a tuple within a relation. Mya contain additional attributes that are not necessary for unique identification.

Question 7

Candidate Key

Answer 7

A superkey such that no proper subset is a
superkey within the relation. Need uniqueness and irreducibility.

Question 8

Entity Integrity

Answer 8

No attribute of a primary key can be null

Question 8

Entity Integrity

Answer 8

No attribute of a primary key can be null

Question 9

Referential Integrity

Answer 9

If a foreign key exists in a relation, either the foreign key
value must match a candidate key value of some tuple in
its home relation or the foreign key value must be wholly
null.