Keys in DBMS

A _____ is a property of the entire relation, rather than of the individual tuples in which each tuple is unique.

• Rows

• Key

• Attribute

• Field

The subset of a super key is a candidate key under what condition?

• No proper subset is a super key

• All subsets are super keys

• Subset is a super key

• Each subset is a super key

Which one of the following cannot be taken as a primary key?

• Id

• Register number

• Dept_id

• Street

An attribute in a relation is a foreign key if the _______ key from one relation is used as an attribute in that relation.

• Candidate

• Primary

• Super

• Sub

A combination of two or more columns used to identify particular rows in a relation is a(n) _____ .

• record

• field

• composite key

• foreign key

Can we define more than one primary key?

• Yes

• No

Which key is used to make relations between two tables?

• Foreign

• Primary

• Candidate

• Composite

Those Candidate keys which are not currently selected as the Primary Key, are called as -

• Super Key

• Foreign Key

• Alternate Key

• Composite Key

A column in the child table that references a Primary key of the parent table is called as

• Candidate Key

• Foreign Key

• Composite Key

• Super Key

Minimal Super keys are called

• Schema keys

• Candidate keys

• Domain keys

• Attribute keys