Question

Which of following statement is NOT correct?

Select one:
a. Every relation must have only one primary key
b. Unique key is also a candidate key
c. Two tuples can have the same values on primary key's components
d. Primary key may be include more than one attribute

Answer 1

The statement that is NOT correct is option a. Every relation must have only one primary key. In a relational database, a primary key is a unique identifier for a record in a table, but a relation can have multiple primary keys if it is a composite key made up of multiple attributes.

Step-by-step explanation:

The statement that is NOT correct is option a. Every relation must have only one primary key. In a relational database, a primary key is a unique identifier for a record in a table. It is used to uniquely identify each row in the table. However, a relation can have multiple primary keys if it is a composite key made up of multiple attributes. For example, in a table of students, the primary key could be the combination of the student's ID number and their last name, which together uniquely identifies each student.