Employees disapear from the roster

[MaMaKow]

The primary key of the table
Dienstplan
is
VK + Datum + Dienstbeginn
which is logical, because no one person can start working more than once at the same time. However, if on another branch the same employee is planned with the start of duty at the same time, it disappears from the first roster without warning.

Options:

1. Change the primary to VK + Datum + Dienstbeginn + Mandant
2. Test for this specific case before writing the data to the database and issue a warning/error to the user.