Question

Simple example of a primary key

Answer 1

Answer:

example, students are routinely assigned unique identification (ID) numbers, and all adults receive government-assigned and uniquely-identifiable Social Security numbers.

Explanation:

Answer 2

roll _no column in the student table  

Explanation:

• The primary key is the key which objective to find a unique record in the database management system.The value of the primary key never is blank.
• In the student table the roll_no column of the student is used to find the unique record of the student so roll_no is the primary key in the student table we do not choose the name , address , dob column as a primary key in the student table because it may be possible two students have the same name, same address and same dob but the roll_no of two students will never be same that's why roll_no is the primary key.

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