I'm trying to develop an attendance management system in vb.net with only 1 primary user which will be the professor. I try putting it in a class diagram but I'm not entirely sure if it's right.
Basically the logic of the system is: a professor can login or create an account. Once logged in, there will a choice such as view profile which lets the user view or edit their profile. A block/section where they can add another section or remove. A block consists of students. When a block is removed students enrolled in that block will also be deleted. And attendance when the user can view, update and make new attendance.
I tried something like this but I feel like something is wrong with it. This is my first time using uml diagram:
When starting designing in OOP, a good advice is to prefer composition over inheritance. With this in mind, let's look at your inheritance relationships (the arrows with the big hollow arrow head):
Is a professor an account? Can a professor be used wherever you use an account? In view of your narrative, it could be ok. However, I would recommend to avoid it, because we could imagine that a user could manage the attendance of several professors. Moreover, the professor doesn't seem to need the account features. A simple association would therefore be a more robust alternative.
Is a student a block? Can a student be used wherever you use a block? That answer to this question is a clear NO according to your narrative: "A block consists of students". A simple association would be the correct alternative.
The statement "When a block is removed students enrolled in that block will also be deleted." could suggest that a composite aggregation (black diamond). It is not clear however if the enrolment of the student is deleted or the student. Again, I'd recommend to stay with a simple one to many association.
Is an attendance really a "schedule"? Can an attendance be used instead of a "schedule"? Your narrative doesn't allow to conclude. I have my doubts, and would suggest to consider making the attendance an association class between professor and schedule.
Another advice, is to use composite aggregation (black diamond) wisely and rather avoid it when it's not absolutely necessary, as it means deleting objects in cascade. This advice applies to all three composite aggregation of the professor.
There are probably other concerns, but these are the most striking ones whereas the others are too detailed in view of your question.