Hello guyz,i am new to daatbase and class diagram.I just get scenarios from internet and try to develop ERD and Class Diagram for them.But the following scenario has caused me some problems, and i am not sure about my design.

"Whenever an employee fills leave application form, the leave application should be appeared for approval to his/her team leader. Team Leader has the option to change the date of requested leave and to approve or reject the leave. Employee also has the option to change date of previously unapproved leaves or to cancel any of unapproved leave. In case of team leader, he can approve his own leaves.

Management should be able to create categories of leaves like (Casual, Sick, Planned work, etc) and should be able to adjust the days allocated to each type of leave".

I have identified these as entities for ERD

1) Employee(I think i dont need to make entity for Technical lead,since he is an employee) 2) LeaveHistory 3) LeaveCategory

Plz correct me if the system need more classes or entities