This query in Linq to Sql - linq-to-sql

Question

i have in my DB table TBus fields like s1,s2.s3.s4,...sn
i get the seatNumber as a parameter and want to get that field just like i have it in my code.
Any idea please.
private string checkSeatValue(int busTripId, int seatNumber)
{
string sNumber = "s" + seatNumber.ToString();
// Some code here
string sqlCommand = "SELECT " + sNumber + " FROM TBus WHERE Id=" + busTripId + "";
// More code here
}

Answer 1

If you want pure Linq2SQL code, you should get the TBus object:
var bus = yourDataContext.GetTable<TBus>().Where(bus => bus.BusTripId == busTripId).SingleOrDefault();
And then switch your seat variable to get the desired field:
var seat;
switch(seatNumber)
{
case "s1":
seat = bus.Seat1;
break;
case "s2":
seat = bus.Seat2;
break;
// And so it goes on...
}
However, you can do pure SQL code via Linq also or play with reflection.
-- EDIT
As I said in the comment, I believe your database model can be improved. My advice would be having two tables:
TBus Table
TBusId - int [PK]
...
TBusSeat Table
TBusSeatId - int [PK]
TBusIs - int [FK referencing TBus.TBusId]
SeatNumber - int
...
That way, you have more natural flexibility to deal with those king of situations. Consider the following set of data:
TBus Table
TBusId
------
1
2
TBusSeat Table
TBusSeatId | TBusId | SeatNumber | PassengerName
------------------------------------------------
1 1 1 Josh Doe
2 1 2 John Doe
3 1 3 Jane Doe
4 2 1 Jack Doe
So, to deal with your desired query with Linq2SQL, it would be simple as this:
var seat = yourDataContext.GetTable<TBusSeat>().Where(seat => seat.TBusId == 1 && seat.SeatNumber == 2).SingleOrDefault();
And calling seat.PassengerName would result in John Doe.