This is mentioned just in case you come across them and wonder. The way to design a database is using an ERD.
An ERD shows the entities (which will become tables). It also shows the relationships between those entities.
The ERD will normally be backed up with data dictionaries for each table. These give added information about each table including details about the fields and their attributes. There are proper ways to do ERDs but they are basically boxes (the tables/entities) and arrows:
In English that might be said "One doctor carries out many appointments".
PHPMyAdmin is commonly used to administer MySQL databases and it combines ERDs and data dictionaries in a way you have already seen:
In a complex relational database ERDs are a useful way to summarise the structure of the database.
