Introduction to Relational Algebra
Learn what Relational Algebra is and why it forms a fundamental foundation for database systems.
We'll cover the following...
Imagine we’re managing our OnlineStore and the marketing team asks a simple question: Can we get a list of all customers who are in the VIP tier? Or maybe the inventory team wants to know: Which of our products cost more than $500?
To answer these questions, we need a way to precisely ask the database to filter, pick, and present the exact information we need. While we’ll eventually use SQL to do this, it’s crucial to first understand the language the database uses to think. That language is Relational Algebra.
It’s the foundational recipe book for every query we run.
By the end of this lesson, we’ll be able to:
Understand what Relational Algebra is and why it’s the theoretical backbone of SQL.
Use the fundamental Select operator to filter data rows.
Use the fundamental Project operator to choose specific data columns.
Use the Rename operator to change the names of tables and columns for clarity.
Let’s dive in and learn how to speak the database’s native language!
Relational algebra
Think of relational algebra as a set of mathematical operations designed specifically to manipulate tables (or relations, as they are formally called). It is a procedural query language, meaning that it provides the database with a step-by-step procedure for retrieving the desired data. Each operation takes one or more tables as input and produces a new table as output.
Relational algebra is important for several reasons: