Managing Indexes

Imagine running a store with thousands of products and customer orders. Without a structured way to locate information quickly, finding data in a massive table can become time-consuming, and queries may become slower and slower with the inclusion of new data. This is where indexes come into play. They act like the index of a book, allowing us to retrieve information swiftly without scanning the entire dataset.

Let’s learn how to create, use, and manage indexes effectively. We’ll go step by step to:

• Understand what an index is and why it is important.

• Learn how to create a simple index.

• Learn how to create a composite index when we have more than one column to speed up.

• Learn how to drop an index we no longer need.

What is an index, and why do we need it?

Indexes are special data structures that databases use to speed up data retrieval operations on a table. They work similarly to a book’s index, where we can quickly look up the right page instead of flipping through every page. Similarly, in the context of the OnlineStore database, if we often query products by ProductName, creating an index on the ProductName column can significantly reduce the query time.

However, indexes do come with a cost. Each index requires additional storage, and each time we insert, update, or delete rows, the index must also be updated. This means there is a trade-off between faster reads and potentially slower writes.

Key benefits:

• Queries with conditions, such as WHERE, or JOIN, on indexed columns execute faster.

• Indexes can significantly enhance operations like ORDER BY and GROUP BY. ...