MSSQL DATABASE INTERVIEW QUESTIONS

What is a UNIQUE constraint in MSSQL, and why is it used?

How do you add a UNIQUE constraint to a new table in MSSQL?

How do you add a UNIQUE constraint to an existing column in MSSQL?

Can a table have multiple UNIQUE constraints in MSSQL, and how would you define them?

How do you handle duplicate values when adding a UNIQUE constraint to an existing column in MSSQL?

How do you drop a UNIQUE constraint from an existing table in MSSQL?

How do you create a UNIQUE constraint on multiple columns (composite unique constraint) in MSSQL?

How do you handle conflicts when inserting data into a table with a UNIQUE constraint in MSSQL?

How do you use the IGNORE_DUP_KEY option with a UNIQUE constraint in MSSQL?

Explain a scenario where using a UNIQUE constraint is crucial for a business application in MSSQL and describe how you would implement it.