Creating a database for students the institute I am working at wants to create a database for students. I have to find the best and easiest solution for this application and I need your opinions.

We would like to create a website/web application where students can enter their data into a form, without having access to the database.
Once the data has been entered, the students shouldn't be allowed to change the data entered.

The institutes employees should then be able to access the database and enter some more data, like thesis deadline.

It is fairly important to us to be able to export a student's data into a .pdf form
.

We would also like this data to be automatically deleted after a defined number of years(5 or 10 years), maybe after automatically sending a notification to the datamanager.

Because of hacking worries, the institute wants this website to be only accessed locally. What this means is that in order for a student to be able to enter his data, he will have to come and use the institute's computers.


We've been thinking about using MS Access but I guess a CMS would be the solution in this case. Now I only need your opinions on which CMS-platform to use for this kind of application. The main focus should be the ease of use, both for me creating it and the employees using it. I also need to be able to find documentation (books, tutorials, how-to's) for it.
For learning, teaching, and assessing I'd recommend an open source system called moodle  (https://moodle.com/moodle-lms/).  It can probably do all you ask for, and much more eg online assessments with time locks (or protected by passwords).  It is also good for keeping students' work, for sending messages to students (or giving feedback on documents or archives sumitted by students), for grouping students into classes - which then have different access permissions for teaching materials etc etc.  

There is a lot of documentation available for it ( see https://docs.moodle.org/33/en/Main_page ).  I recommend that you have a look at this.  You can configure a server (or VM) so that it is only accessible on your institute's LAN.

I'd recommend against developing your own application.  Rather spend the time/money/energy to set this up the way it is beneficial for you.  There's - of course - much more to be said or written about this, but: have a look, try it out, maybe you will find it useful.  I am not associated with the company or the project.  However, having used other VLEs (virtual learning environments) in the past, I would preferably use moodle.