In the broadest definition, a database is anything that collects and organizes data. A spreadsheet holding customer bookings is a database, and so is a plain-text file containing flight schedule data. Plain-text data itself can be stored in a variety of formats, including XML and CSV.
Professionally, however, when one refers to a “database” they likely are referring to a relational database management system (RDBMS). This term may sound technical and intimidating, but an RDBMS is simply a type of database that holds one or more tables that may have relationships to each other.
Exploring Relational Databases
A table should be a familiar concept. It has columns and rows to store data, much like a spreadsheet. These tables can have relationships to each other, such as an ORDER table that refers to a CUSTOMER table for customer information.
For example, suppose we have an ORDER table with a field called CUSTOMER_ID (Figure 2-1).
Figure 2-1. An ORDER table with a CUSTOMER_ID
We can reasonably expect there to be another table, maybe called CUSTOMER (Figure 2-2), which holds the customer information for each CUSTOMER_ID.
Figure 2-2. A CUSTOMER table
When we go through the ORDER table, we can use the CUSTOMER_ID to look up the customer information ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month, and much more.
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.
Julian F.
Head of Cybersecurity
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.
Addison B.
Field Engineer
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.
Amir M.
Data Platform Tech Lead
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.
