Summary  
This chapter introduces the concepts of databases and DBMSs and explains the differences between relational and non-relational database models.  

General domain of usage  
Data persistence and management

## Basic Concepts
Databases are ubiquitous, but no single database model can cater to the diverse needs of various projects and servers. There's a spectrum of database types and database management systems.

- **Database (DB)** is a repository of information;

- **Database Management System (DBMS)** offers a suite of tools to manage and interact with a database. It allows users to oversee the data, structure the database, and provides an interface for these operations.

Primarily, there are two database models: **relational** and **non-relational**. Additionally, there are multi-model database management systems, such as **Oracle Database**.

**Non-relational databases** encompass a variety of types, including document data stores, column-oriented databases, key-value stores, and graph databases.

This course delves into the theory behind relational databases. You'll learn what they are and see how they differ from non-relational databases. Throughout the course, we'll walk you through the ins and outs of database design and familiarize you with various types of relationships. Additionally, you'll explore the concepts of normalization and normal forms, equipping you with the knowledge to craft efficient and optimized databases.

This section dives into the world of relational and non-relational databases, teaching you how to visually represent database structures.

We'll dive deep into relational databases, giving you a thorough understanding of essential concepts. This includes topics like foreign keys, various ON DELETE options, and the different types of relationships.

Ready to build a database? This section will hone your skills, emphasizing the importance of a well-structured database for peak performance. Here, you'll grasp the fundamental principles of crafting user-friendly databases.

Introduction

Basic Concepts

The most popular databases

1. What models are databases divided into?

2. Choose relational databases:

3. Choose non-relational databases: