I have two databases, one called management and the other named departments.
If a user creates a department, management products, and another user deletes management products. When the first user saves the department, is expelled from the program and receives an exception. How can block the second user can not delete management products, if involved in a transaction. (The second user can not delete management products, if the first user is involved in creating this department on the management but did not save)
" Object Reference not intance of an object "