SQL Server Course for Beginners with 100+ examples - UPDATE Statement

The video tutorial explains key constraints in SQL, focusing on primary and foreign keys. It describes how primary keys uniquely identify records in a table, using an employee table as an example. The tutorial then introduces foreign keys, which reference primary keys in another table, and explains their role in maintaining data integrity by preventing invalid data entries. The video also covers the creation of foreign key constraints and the relationship between parent and child tables.

What is the main function of a primary key in a table?

• To store foreign data

• To allow duplicate records

• To uniquely identify each record

• To reference another table

In the context of SQL, what is a foreign key?

• A key that uniquely identifies a record in its own table

• A key that references a primary key in another table

• A key that allows duplicate values

• A key that is not related to any other table

Which table is considered the child table in the given example?

• Neither table

• Both tables

• Department table

• Employee table

Why are foreign keys important in maintaining data integrity?

• They duplicate data across tables

• They allow any data to be inserted

• They prevent invalid data from being inserted

• They remove the need for primary keys

What is the relationship between a foreign key and a primary key?

• A foreign key is the same as a primary key

• A foreign key references a primary key in another table

• A foreign key is unrelated to a primary key

• A foreign key duplicates a primary key