SQL Server 2008 - Check For Row Changes

Instead of using a ton of or statements to check if a row has been altered I was looking into checksum() or binary_checksum(). What is best practice for this situation? Is it using checksum(), binary_checksum() or some other method? I like the the idea of using one fo the checksum options so I don't have to build a massive or statement for my update.

EDIT: Sorry everyone, I should have provided more detail. I need to pull in data from some outside sources, but because I am using merge replication I don't want to just blowout and rebuild the tables. I want to only update or insert the rows that really have changes or don't exist. I will have a paired down version of the source data in my target db that will get sync'd down to clients. I was trying to find a good way to detect the开发者_StackOverflow中文版 row changes without having to look at every single column to perform the update.

Any suggestions is greatly appreciated.

Thanks,

S

First, if you are using actual Merge replication, it should take care of updating the proper rows for you.

Second, typically the way to determine if a row has changed is to use a column with a data type of timestamp, now called rowversion, which changes each time the row updated. However, this type of column will only tell you if the value changed since the last time you read the value which means you have to have read and stored the timestamps to use in comparison. Thus, this may not work for you.

Lastly, a solution which may work for you would be triggers on the table in question that update an actual DateTime (or better yet, DateTime2) column with the current date and time when an insert takes place. Your comparison would need to store the datetime you last synchronized to the table and compare that datetime in the last updated column to determine which rows had changed.

It might help if we have a bit more info about what you are doing but in general the checksum() option does work well as long as you have access to the original checksum of the row to compare to.