In the computing world it is common to hear terms like “Camel Case”, “Snake Case”, “Pascal Case” etc. But don’t be alarmed!
We will not deal with snakes or camels despite being used in the name of these ways of writing.
Snake case (or snake_case) is the way to write compound words separated by an underscore (_) instead of using a space.
Everything is usually written in lowercase. Example: “hello_world”, “first_name”
It is widely used in computer code, mainly in SQL databases field name.

SQL is case-insensitive. Many databases fold names to lowercase when creating tables, so capitalisation is lost.
The only portable way to preserve “words” within names is to use snake case.

Snake Case (All Caps)

In computer programming, when used with all capital letters, it is often used as a convention in declaring constants in several languages.