"A dependent property in a ReferentialConstraint is mapped to a storage-generated column. Column: 'employee_id'."}

var emp_assigment = new EMPLOYEES_ASSIGNMENT
                                        {
                                            from_date = gvRowAssigment.Cells[0].ToString(),
                                            to_date = gvRowAssigment.Cells[1].ToString(),
                                            area = gvRowAssigment.Cells[2].ToString(),
                                            sector = gvRowAssigment.Cells[3].ToString(),
                                            company_name = gvRowAssigment.Cells[4].ToString(),
                                            description = gvRowAssigment.Cells[5].ToString(),

                                            
                                            employee_id = emp.employee_id,
                                            assigment_id = new Random().Next(),
                                            
                                            
                                            EMPLOYEES_ASSIGMENT_TOOLS = emp_assig_tools,

                                            assigment_tools_id =   emp_assig_tools.assigment_tools_id,
                                            
                                            EMPLOYEES_ASSIGMENT_TECHNOLOGY = emp_assig_teh,
                                            assigment_technology_id = emp_assig_teh.assigment_technology_id,
                                            
                                            EMPLOYEES_ASSIGMENT_REFERENCE = emp_assig_ref,
                                            reference_id = emp_assig_ref.reference_id
                                        };


                emp.EMPLOYEES_ASSIGNMENT.Add(emp_assigment);
 }