Transactions/Locks in Sql Server
SQL Server has very extensive locking options. Most are automatic but you can force them if needed for specific cases. You can also implement non-default locking behaviour on various levels. What you are looking for (as far as I can tell) can best be handled by a table hint called rowlock. Depending on your isolation level, you might need additional hints to ensure its function. You can read more about it in the following link: https://msdn.microsoft.com/en-us/library/ms187373.aspx