MariaDB Crash Course - Ben Forta [4]
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Note
A Note presents interesting pieces of information related to the surrounding discussion.
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Tip
A Tip offers advice or teaches an easier way to do something.
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Caution
A Caution advises you about potential problems and helps you steer clear of disaster.
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New Term
Provides clear definitions of new, essential terms.
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Input
The Input icon identifies code that you can type in yourself. It usually appears next to a listing.
Output
The Output icon highlights the output produced by running MariaDB code. It usually appears after a listing.
Analysis
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1. Understanding SQL
In this chapter, you learn about databases and SQL, prerequisites to learning MariaDB.
Database Basics
The fact that you are reading this book indicates that you, somehow, need to interact with databases. And so before diving into MariaDB and its implementation of the SQL language, it is important that you understand some basic concepts about databases and database technologies.
Whether you are aware of it or not, you use databases all the time. Each time you select a name from your e-mail address book, you are using a database. If you conduct a search on an Internet search site, you are using a database. When you log in to your network at work, you are validating your name and password against a database. Even when you use your ATM card at a cash machine, you are using databases for PIN verification and balance checking.
But even though we all use databases all the time, there remains much confusion over what exactly a database is. This is especially true because different people use the same database terms to mean different things. Therefore, a good place to start our study is with a list and explanation of the most important database terms.
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Tip: Reviewing Basic Concepts
What follows is a brief overview of some basic database concepts. It is intended to either jolt your memory if you already have some database experience, or to provide you with the absolute basics, if you are new to databases. Understanding databases is an important part of mastering MariaDB, and you might want to find a good book on database fundamentals to brush up on the subject if needed.
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What Is a Database?
The term database is used in many different ways, but for our purposes a database is a collection of data stored in some organized fashion. The simplest way to think of it is to imagine a database as a filing cabinet. The filing cabinet is simply a physical location to store data, regardless of what that data is or how it is organized.
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New Term: Database
A container (usually a file or set of files) to store organized data.
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Caution: Misuse Causes Confusion
People often use the term database to refer to the database software they are running. This is incorrect, and it is a source of much confusion. Database software is actually called the Database Management System (or DBMS). The database is the container created and manipulated via the DBMS. A database might be a file stored on a hard drive, but it might not. And for the most part this is not even significant as you never access a database directly anyway; you always use the DBMS, and it accesses the database for you.
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Tables
When you store information in your filing cabinet you don’t just toss