Manage exceptions when selecting, modifying data

The SqlException has a Number property that you can check.

catch (SqlException e)
{
   switch (e.Number)
   {
      case 2601: // duplicate error
         // Do something.
         break;
      default:
         throw;
   }
 }

The following table describes the possible values for this property:

Source of Error	SqlError.Number	SqlException has inner Win32Exception (beginning with.NET Framework 4.5)
Error from server	Server error code This number corresponds to an entry in the master.dbo.sysmessages table.	No
Connection timeout	-2	Yes (Number = 258)
Communication error (non-LocalDB)	Win32 error code	Yes (Number = Win32 error code)
Communication error (LocalDB)	Win32 error code	No
Encryption capability mismatch	20	No
Failed to start LocalDB	Win32 error code	No
Read-only routing failure / Server had severe error processing query	0	No