Dear
we are creating a form to questionnaire for a research university, users have the name and its registration number,
are in csv.
so would like to know if it is possible and how it performs.
for example:
the User to enter your registration number, be found in the mysql database (we will import into a mysql csv) if you are there you can answer the research questions and every time he sending the form will be registered over the previous (update earlier).
how can we make to us whatever be the rsjoomla or Pro
Thank

You can try using the $invalid method, as explained here:

https://www.rsjoomla.com/support/documentation/view-article/602-php-scripts.html

or creating your own custom validation rule:

https://www.rsjoomla.com/support/documentation/view-article/75-custom-validation-rules.html