Chapter 1: Introduction to Databases
Data has become increasingly important over the last few years. Almost all applications use data, whether the application is a Customer Relationship Management (CRM) system at work or a social media app on your phone. All that data is stored in databases. Since the 1980s, almost all those databases have been relational databases. Nowadays, with the advent of big data, there are different ways to store and process huge amounts of data. Some of them can be classified as so-called NoSQL databases. NoSQL stands for "not only" SQL. This means that we are seeing other types of databases emerge and being used alongside relational databases. NoSQL databases are important in the area of big data. The "SQL" in NoSQL stands for Structured Query Language. This is the programming language of relational databases and has become the "equivalent" of relational databases.
In this chapter, you will learn the basics of databases. A lot of the theory discussed in this chapter stems from relational databases, although the majority is applicable to other database systems as well.
We will discuss the following topics in this chapter:
- Overview of relational databases
- Introduction to Structured Query Language
- Impact of intended usage patterns on database design
- Understanding relational theory
- Keys
- Types of workload