What Are Primary Keys in SQL? Explained with Examples скачать в хорошем качестве

What Are Primary Keys in SQL? Explained with Examples

In this video, I explain what primary keys are in SQL databases, why they are important, and how to create them. You will learn: • What a primary key is and how it ensures data integrity • Why primary keys prevent duplicates and accidental updates or deletions • How primary keys help build relationships between tables • The rules of primary keys, including null values and one primary key per table • The difference between simple and compound primary keys • How to create primary keys in new tables and add them to existing tables I also walk through practical examples showing how to pick the right primary key for a table and how SQL automatically creates a clustered index when you define one. By the end of this video, you will have a clear understanding of primary keys, their purpose, and how to use them effectively in SQL. Instagram:   / sql.handbook