Creating a database for students
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.