Being cognizant of storage and indexing implications is important, but I would still probably go the char/varchar route; a distinction should be made between nu

Being cognizant of storage and indexing implications is important, but I would still probably go the char/varchar route; a distinction should be made between numeric data and text data that happens to be comprised only of numeric values. In addition whether talking about SSNs, product numbers, whatever, if you try and use a numeric field you run the risk of coming across a value that exceeds the upper bound of numeric type.