DEV Community

Cover image for Streamlining SQL Data Management with Generated Columns
DbVisualizer
DbVisualizer

Posted on

Streamlining SQL Data Management with Generated Columns

Generated columns in SQL automatically compute and store data, simplifying database operations. This article offers a brief overview and practical examples to demonstrate their use.

Examples of SQL Generated Columns

In SQL, generated columns are defined via CREATE TABLE or ALTER TABLE. Here’s an example using MySQL:

ALTER TABLE users
ADD COLUMN fullName VARCHAR(255) AS (CONCAT(name, " ", surname)) STORED;
Enter fullscreen mode Exit fullscreen mode

This adds a stored column fullName that concatenates name and surname.

For a virtual column, which doesn’t use storage space:

ALTER TABLE users
ADD fullNamePoints VARCHAR(255) AS (CONCAT(fullName, " (", points, ")")) VIRTUAL;
Enter fullscreen mode Exit fullscreen mode

FAQs About Generated Columns

What databases support generated columns?
Databases like MySQL, MariaDB, PostgreSQL, SQL Server, and Oracle support generated columns.

What is the difference between a trigger and a generated column?
Triggers execute scripts on events affecting multiple tables, whereas generated columns store auto-calculated data in one table.

What are the types of columns generated in SQL?
SQL has stored (precomputed) and virtual (computed on-the-fly) generated columns.

What is the difference between a generated column and a regular column?
Generated columns are auto-calculated and immutable, unlike regular columns which are manually updated.

Conclusion

SQL generated columns automate data calculations, enhancing database efficiency. For an in-depth guide and more examples, check out The Ultimate Guide to Generated Columns.

Image of Timescale

Timescale – the developer's data platform for modern apps, built on PostgreSQL

Timescale Cloud is PostgreSQL optimized for speed, scale, and performance. Over 3 million IoT, AI, crypto, and dev tool apps are powered by Timescale. Try it free today! No credit card required.

Try free

Top comments (0)

A Workflow Copilot. Tailored to You.

Pieces.app image

Our desktop app, with its intelligent copilot, streamlines coding by generating snippets, extracting code from screenshots, and accelerating problem-solving.

Read the docs

👋 Kindness is contagious

Dive into an ocean of knowledge with this thought-provoking post, revered deeply within the supportive DEV Community. Developers of all levels are welcome to join and enhance our collective intelligence.

Saying a simple "thank you" can brighten someone's day. Share your gratitude in the comments below!

On DEV, sharing ideas eases our path and fortifies our community connections. Found this helpful? Sending a quick thanks to the author can be profoundly valued.

Okay