SQL Server Course for Beginners with 100+ examples - FOREIGN KEY Constraint

The video tutorial explains the NOT NULL constraint in SQL, which ensures that a column cannot have null values. It demonstrates how to create a table with NOT NULL fields and insert data into it, highlighting the importance of NOT NULL in maintaining data integrity. The tutorial uses an example of an employee table to illustrate these concepts.

What is the primary purpose of the NOT NULL constraint in SQL?

• To allow duplicate values in a column

• To ensure a column cannot have null values

• To automatically generate unique values

• To enforce a specific data type

When defining a table, which SQL command is used to create it?

• ALTER TABLE

• INSERT INTO

• SELECT FROM

• CREATE TABLE

Which field in the example table is set as NOT NULL?

• City

• Salary

• Employee Name

• Department

What happens if you try to insert a null value into a NOT NULL column?

• The null value is accepted without any issue

• The null value is automatically converted to zero

• An error is generated

• The database ignores the null value

Which SQL command is used to insert data into a table?

• SELECT

• UPDATE

• INSERT INTO

• DELETE