Introduction to Databases: Learn the Essentials

Posted on June 19, 2019 by Aaron TurnerAaron Turner

What Are Databases, Anyway?

A database is, essentially, an organized collection of data. That’s it. There are no big words here, no complex diagrams. They’re both essential and often misunderstood. Many an introduction to database basics overcomplicates this, but we’re aiming for straightforward. A database is just a simple, organized collection of data.

Working with Databases

Great. People have databases. What can we do with them? And How?

Well, there is something called DBMSs (database management systems), and they allow us to use an understandable language to work with our data. There are also things called statements that we utilize to search through, update, and delete our data.

Types of Databases

There are a couple of different types of databases. Let’s look at the flat file type and another called relational.

Flat File

These are usually used for storing things like configuration data. The /etc/passwd and /etc/fstab files found on Linux systems are good examples of flat file databases. Each line of these files contains information (a record) with each field of the record (name, ID, etc.) separated by a character (like a tab, colon, or space). Then each record is separated by something else, like a newline character, or semicolon. Different flat file databases use different delimiters.

Relational

And no introduction to databases would be complete without talking about relational databases. These are some of the ones even non-technical people will have heard of, like MySQL, Oracle, and Microsoft SQL Server. These are a whole different animal than flat file databases.

Think of a relational database as a collection of spreadsheets. Each one is called a table. We can have a database with hundreds of tables, and the data in each of them is related to data in the other ones. This means we can ask a question (a query) and be pulling data from any of them. Something like: Show me everyone in the people table, that has an animal in the pet table, with an Iowa address in the homes table, who drives a sedan as referenced in the vehicles table. Pretty crazy, huh? Once anyone gets the hang of Standard Query Language, things like that are easy. You can see what a powerful tool relational databases can be.

Where to Begin

Before anyone can get into the real incredible aspects of working with databases, they’ve got to learn the basics. Linux Academy has just the thing. Our own Mike McClaren has created an introduction to databases course, aptly named Database Essentials. He’ll walk students through the basics of several different database flavors. The course includes hands-on labs for each system, presenting you with your own environment to follow along and learn at your own pace. Once you’ve mastered the essentials of databases, we’ll help you figure out where to go from there.

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