Essential SQL Server Constraints Interview Questions & Answers:

1. What are constraints in Microsoft SQL Server?

Constraints enforce the data integrity to the database and protect columns of the table from unwanted values. NOT NULL, CHECK, UNIQUE, PRIMARY KEY, FOREIGN KEY are the types of contraints define in SQL Server.

2. What is default constraint in MS SQL Server?

Default constraint is used to fill column with default value defined during creation of table if nothing is supplied while inserting data. IDENTITY columns and timestamp columns can't be associated with default constraint.