Relational model

Question 1

Relation

Answer 1

Table with columns and rows

Question 2

Attribute

Answer 2

Named column of a relation

Question 3

Tuple

Answer 3

Row of a relation

Question 4

Domain

Answer 4

Set of allowable values for one or more attributes

Question 5

Degree

Answer 5

Number of attributes a relation contains

Question 6

Cardinality

Answer 6

Number of tuples a relation contains

Question 7

Intension

Answer 7

Structure of the relation including its domains

Question 8

Extension

Answer 8

Set of tuples currently in the relation

Question 9

Superkey

Answer 9

Set of attributes that uniquely identifies a tuple in a relation

Question 10

Candidate key

Answer 10

Minimal set of attributes that uniquely identifies a tuple in a relation

Question 11

Primary key

Answer 11

Candidate key designated as the distinguishing key of a relation

Question 12

Foreign key

Answer 12

Set of attributes in one relation referring to the primary key of a relation

Question 13

Domain constraint

Answer 13

Every value of an attribute must be an element of the attribute’s domain or be null

Question 14

Entity integrity constraint

Answer 14

No attribute of a primary key can be null

Question 15

Referential integrity constraint

Answer 15

If a foreign key exists in a relation, then the foreign key value must match a primary key value of a tuple in the referenced relation or be null