DSXchange

I have always felt that source / ERP systems should store data as uppercase to eliminate duplication and redundancy as much as possible. This is not the case in our organization sot I've suggested to the ETL team that data be extracted as uppercase for the DWH.

What is the best practice around this? Does anybody know of an international standard?

There is no standard, but most character data fields do need to be stored in mixed case and rely on differentiation between upper and lower case. Names, Addresses and clear text become almost unreadable in uppercase; but some key/code/mnemonics columns should be in one case or the other to avoid inadvertant case duplicates.