External Dependenices

In back-end development, databases and queues are essential external dependencies that are often used to store and manage data and to communicate between different services. In this lesson, we’ll discuss why we need these external dependencies and how they are used in modern back-end systems.

Databases

Databases are used to store and manage data in back-end systems. They provide a way to persist data so that it can be accessed and used later. There are many different types of databases, such as relational databases (like MySQL and PostgreSQL) and NoSQL databases (like MongoDB and Cassandra).

Why do we need databases?

We need databases because they provide a way to store data that can be easily accessed and manipulated. Without a database, we would need to store all data in memory, which is not practical for large amounts of data. Additionally, databases provide different features, like data indexing and querying, which make it easy to find and retrieve data quickly.

How are databases used in back-end systems?

Databases are typically used to store data that needs to be persisted, such as user data, product data, or transaction data. In a typical back-end system, there might be multiple services that interact with a database, either to read or write data.

Here is a simple diagram that illustrates how a database fits into a typical back-end system: