与表中的LastModifyOn（DateTime）列相比，使用rowversion（timestamp）有什么好处？

Question

Problem:

I am working on asp.net application and my Intention is to confirm that a table row is updating only when it is not updated in between a user's request and submit .

Scenario

1. User X and Y open same invoice(invoiceid=12) in different browser
2. User X changed invoice date to 1-july-2014 in UI.
3. User Y changed invoice date to 5-july-2014 in UI
4. User X press submit button.-- Invoice date changed to 1-july-2014
5. User Y press submit button.-- Invoice date changed to 5-july-2014.

X and Y both did not know whether invoice data are not altered in between.

Solution-1

1. We added a column LastModifyOn(DateTime) in invoice table
2. When retrieve the invoice data for edit also getting LastModifyOn column data
3. Keeping the encrypted LastModifiedOn data in hidden field in UI
4. When user submitting the invoice data changes, we also sending LastModifiedOn to compare.
5. Showing appropriate message.

Solution-2

1. We added a column version(rowversion) in invoice table
2. When retrieve the invoice data for edit also getting version column data
3. Keeping the encrypted version data in hidden field in UI
4. When user submitting the invoice data changes, we also sending version to compare.
5. Showing appropriate message.

X and Y knows whether invoice data are altered in between or not.

Question:

Now my question is what benefit we will get by using version(rowversion) column over LastModifyOn(DateTime)...

Point:

1. We are audit trailing in invoice table so last updated on data is already available.
2. Please mention strong points in reason not like we do not need to update rowversion column explicitly or definition of timestamp ..

Answer 1

It looks as if you have decided (I might add, correctly) that timestamp/rowversion is better than datetime. IMO it is up to you and the purpose. I will try to list down the differences between these two.

• timestamp range is from 1970-01-01 00:00:01 to 2038-01-19 03:14:07; where as datetime range is from 1000-01-01 00:00:00 to 9999-12-31 23:59:59
• timestamp supports timezones where as datetime doesn't
• timestamp is guaranteed to be unique (provided you use it properly) where as datetime is just a datatype and can be manipulated (specified in an insert for example)

PS: From v2008 onwards 'timestamp' is deprecated, so use rownumber (they are synonyms)*.

*Source: http://msdn.microsoft.com/en-us/library/ms182776.aspx