I have a PHP registration form in the MySQL database. After completing the form , the user is redirected to the page cad.php where he says that the registration was successful and in 3 seconds it is redirected to login page.
The problem is that if the user presses to go back, PHP only re-registers with blank data, then creates a line with no information.
I searched the internet about ignoring records with missing data, or Not Null , but I was not successful in the search.