PHP and MySQL multiple registrations at a time

[PvG]

I'm currently studying IT and I'm a beginner with PHP and MySQL.

Though I want to make a registration form for a school.
The registration form consist of three parts (basic info, address info and courses info).
The MySQL database will consist of four tables (users, addresses, users_has_courses and courses).

 

The goal for this registration form is to record all inscriptions in MySQL and maybe into a Excel.
My idea was to store all data into a session, when the registration is complete, the user can confirm and all the data should be read into the MySQL. This insertion would include 1 write to users, 1 write to addresses and multiple writes to users_has_courses.

This form will be used on the registration day, so I expect around ten computers handling the registrations. What happens when some users press the button at the same time? If they are all asking for the next unused ID, they will all select the same ID and write to it? What if I plan to write to a MySQL and Excel after each other, will Excel get the same problems?

Thank you!

 

[Barand]

Don't worry, mysql will allocate a unique insert id to each connection