[Fixed]-How to make good Django model for custom template with dependencies with calendar days?

Simple way is creating a model with a foreign key to Student and a date field, as you stated. Now, in order to make it work with your desired interface, yes, you will probably end up using AJAX calls to create the respective instances of the model. If you don’t want to use AJAX you could generate your checkbox grid with convenient names, so that you can parse those names in the view and the bulk update all your models.