DBMS Summer quiz4

Choose the correct statement regarding superkeys

• A superkey is an attribute or a group of multiple attributes that can uniquely identify a tuple.

• A superkey is a tuple or a set of multiple tuples that can uniquely identify an attribute

• Every superkey is a candidate key

• A superkey is an attribute or a set of attributes that distinguish the relation from other relations

What is a foreign key ?

• A foreign key is a primary key of a relation which is an attribute in another relation

• A foreign key is a superkey of a relation which is an attribute in more than one other relations

• A foreign key is an attribute of a relation that is a primary key of another relation

• A foreign key is the primary key of a relation that does not occur anywhere else in the schema

An attribute is a __________ in a relation.

• Row

• Column

• Value

• Tuple

What is the method of specifying a primary key in a schema description?

• By writing it in bold letters

• By underlining it using a dashed line

• By writing it in capital letters

• By underlining it using a bold line

Statement 1: A tuple is a row in a relation

Statement 2: Existence of multiple foreign keys in a same relation is possible

• Both the statements are true

• Statement 1 is correct but Statement 2 is false

• Statement 1 is false but Statement 2 is correct

• Both the statements are false

State true or false: If a relation consists of a foreign key, then it is called a referenced relation of the foreign key dependency.

• True

• False

Which of the following is a group of one or more attributes that uniquely identify a row?

• Key

• Determinant

• Tuple

• Relation

A relation is considered as

• column

• one-dimensional table

• two-dimensional table

• three-dimensional table

In the relational model , relations between relations or tables are created by using:

• composite keys.

• determinants.

• candidate keys

• foreign keys.

Table is synonymous with the term

• Record

• Relation

• Column

• Field