Database layers are part of many web applications, and MySQL and PostgreSQL are undoubtedly among the basic types of Linux databases. All data with which the website works is stored in the database. Like, for example, a table in Excel, where each individual cell has its own index. Cells can contain a text string, a number, or the path to an image file.

The structure of the database also affects the speed of the web server with the database layer. The website itself can also work with large databases that contain a lot of data. In such a case, database optimization is an essential part of their regular maintenance.