Why do we need a data schema in access?

Question

MySQL

Not so long ago, at the university, in computer science, ms.accesses took place. After creating the tables, it was necessary to draw a data schema there. I passed computer science, and forgot about accessories. Sometimes I use MySQL. But MySQL doesn't require any data schemas. When I need a connection with a table, I simply connect via JOIN. So, I still do not understand why it was necessary to draw the entire data scheme there, what does it give? And is there an analogue of this scheme in MySQL?
It's called the ER Diagram.

Answer 1

In fact, in MySQL, in addition to "just connect via JOIN", there are also "foreign keys" (foreign key) that define relationships between tables (the same ones set by the ER-model) and provide automatic data integrity control.
An ER model is needed in order to describe the subject area. And building an ER model is the initial stage of database design. And already from the finished ER model, the structure of the database tables is automatically generated (which is done not by the DBMS itself, but by separate utilities).
Access is a mishmash of the DBMS itself and the visual controls of this DBMS. And MySQL is just a DBMS. Because MySQL does not contain built-in mechanisms for working with ER.
If you work with MySQL only in phpMyAtmin, then, of course, you will not encounter ER. But the more decent MySQL administration programs contain the mechanisms for working with ER.

Answer 2

An ER diagram is needed not for the operation of the database, but for the developer himself. It allows you to visually display tables and relationships between them. MySQL Workbench allows you to draw an ER diagram and generate commands for creating tables with foreign keys from it, and also knows how to restore an ER diagram from an existing database.