Model first of EF, how to define navigation property relationship without setting foreign key between tables in database

Question

I want to create following two tables,

1. Driver table with following columns(DriverId,DeptId,Version,CarNo, License)
   DriverId is primary key, DeptId,Version,CarNo forms unique keys.

   • DeptId will have duplicate values in this table

2. and I want to create DriverTrips table with (DeptId, TotalIncome) column. My question is in Entity Framework how can I make use of navigation properties, if there is no foreign key relationship ?Is that possible? Basically, I don't want to repeat DeptId values in this table.

I looked at many other posts did not get any answer. Any help to guide me in a right direction is appreciated.