Add new field in table already have 2000 record and calculate in newly created field

I have a table name vehicle with already have near around 2000 record now I want to add a new field Var_Meter . I have done this job from SQL Server now I want to add data in newly added field In_meter-Out_meter=Var_meter . please help I am doing this on ASP.Net C# . I was done this kind of work in Visual Foxpro code just look like select table - Go top - Do While !Eof() replace Var_Meter with In_meter-Out_meter - skip- EndDo please help how can i do this in MVS ASP.net C#. Regards, Abdul Waheed