Cyclone (5/17/2010)
Do you see any problems with this approach?Also, I checked the length (using Len()) of the Hash Value and the max length I have so far is 20. I have the column that holds the Hash Value as datatype varbinary(max). Should I change the size of this column?
Two problems: Why are you converting to upper case and you don't have a delimiter. 'AB' and 'A' will give the same as 'A' and 'BA' with your method. This has been hashed out (pun intended!) in prior conversations; please read the previous comments. It doesn't matter if the delimiter is in your data or not, just that there is something. You can just use a space. As long as something is there to break it up.
Converting to upper case is a little strange - why do it? Check with your SME or data steward to confirm your target system should ignore changes in case. No one here can give the definite answer, although I advise against it unless you have a requirement to do so.
The output is always 20 bytes for sha1 (and 16 for md5) but I don't know if the system needs extra processing or space to handle (max) instead of just (20). It probably doesn't matter.
The point of my article was the xref tables to hold checksums and keys; did anyone notice that at all in the debate over whose hash to use???