spGetLastEReceiptSequence

            CREATE procedure [dbo].[spGetLastEReceiptSequence](@Stack nvarchar(256), @Sequence int out) as
            set @sequence = -1;
            declare @result int;
            exec @result = sp_getapplock @Resource = 'Receipt Stack', @LockMode = 'Exclusive', @LockOwner = 'Session', @LockTimeout = 60000;
            if @result in (0,1) begin -- Success
            select @sequence = coalesce(max(Sequence),-1) from dbo.DonationEReceipt where Stack = @Stack
            exec sp_releaseapplock @Resource = 'Receipt Stack', @LockOwner = 'Session';
            end