public void DeleteFriend(int contactId1, int contactId2)
{
using (var conn = this.Connection)
using (var mc = new MySqlCommand("DELETE FROM `friends` WHERE (`userId1` = @userId1 AND `userId2` = @userId2) OR (`userId2` = @userId1 AND `userId1` = @userId2)", conn))
{
mc.Parameters.AddWithValue("@userId1", contactId1);
mc.Parameters.AddWithValue("@userId2", contactId2);
mc.ExecuteNonQuery();
}
}