🚀 go-pugleaf

Hi
I am coming from desktop application development field and now I am
building(struggling with) my first web application using ASP.NET.
I have several questions about good and bad practices in web programming in
general.
The thing that bothers me is using memory on the server.
Until now for my applications in Delphi, I create a PDF framework to convert
data in Database to objects and collection
of objects. I usually use late binding and if I read some data from table I
keep it in memory in case I need it again. So let say I have a school
database for example. I create a student object, then if user decide to see
courses I read the courses for the student in a courses collection(property
of student  object) and keep this in memory until student object exist. I
mostly use Interfaces and let Delphi release my objects when I do not need
them. This model works great for me and I would like to use it in ASP.NET
application as well.
My problem is that I am not sure that this kind of use of memory is
appropriate for web programming.
I guess I can use one CurrentUser which would be a root object and keep it
in HttpSession. This object can be root for all objects that I will create
and his data will live in memory until current user session is active.
(For example let say student is my user. student object will create courses
, course may create evaluations, and evaluation may create marks. One I read
them they stay in memory)
But still is this kind of use of memory acceptable in web application model
with thousands of active users per second.
On the other hand I do not think I would ever have more than 100 active
users at any time in my application anyway.
Any thoughts and comments will be greatly appreciated

Angel