Exercise 38: Introduction To SQL

The best way to learn how to model and design solid data is to start with the very basic building blocks. The SQL ("sequel") style of database has been the standard for data modeling and storage for many decades. Once you know basic SQL you can easily use just about any NoSQL or object relational mapping (ORM) system out there. SQL is a very formal way to store, manipulate and access data that gives you a formal way to think about it. It's also not very difficult since the language is not Turing complete like a full programming language.

SQL is everywhere, and I'm not saying that because I want you to use it. It's just a fact. I bet you have some in your pocket right now. All Android Phones and iPhones have easy access to a SQL database called SQLite, and many applications on your phone use it directly. It runs banks, hospitals, universities, governments, small businesses, and large ones; just about every computer and every person on the planet eventually touches something running SQL. SQL is an incredibly successful and solid technology.

The problem with SQL is it seems everyone hates its guts. It is a weird obtuse kind of "non-language" that most programmers can't stand. It was designed long before any of these modern problems like "web scale" or object-oriented programming even existed. Despite being based on a solid mathematically built theory of operation, it gets enough wrong to be annoying. Trees? Nested objects and parent child relationships? SQL just laughs in your face and gives you a massive flat table saying, "You figure it out bro."

Why should you learn SQL if everyone hates it so much? Because behind this supposed hate is a lack of understanding of what SQL is and how to use it. The NoSQL movement is partially a reaction to antiquated database servers and also a response to a fear of SQL borne from ignorance of how it works. By learning SQL, you actually will learn important theoretical concepts that apply to nearly every data storage system past and present.

No matter what the SQL haters claim, you should learn SQL because it is everywhere, and it's actually not that hard to learn enough to be educated about it. Becoming an educated SQL user will help you make informed decisions about what databases to use, whether to not use SQL, and give you a deeper understanding of many of the systems you work with as a programmer.