PHP is a widely used server scripting language. It's vast capabilities and lightweight nature makes it ideal for web frontend developing, and while it is possible to create advanced structures in it, it's basic usage also easy to learn, which makes it a good starting point for beginners also. The data recorded, processed, sent or displayed by the application we build is need to be stored somewhere, however; our webpage is stateless without this data. We can store our data in many ways or even discard it after use, but the most standard way is storing it in a database designed for the sole purpose of storing data in a reliable way, and present it if needed, as fast as possible.
This is a companion discussion topic for the original entry at https://linuxconfig.org/persisting-data-into-a-posgresql-database-with-php