that depends on your requirement. If you need to join on them or need to concatenate with other fields, you will find some of the limitations will have an impact.
With regards your original question, you will find properties like format in the tabledef - it is not something you can specify with sql.
with regards values, you will need to check what value is what for format. set a field as required then use vba to interrogate the tabledef to find the property and the value - see these links
http://www.java2s.com/Code/VBA-Excel...properties.htm
https://www.tek-tips.com/viewthread.cfm?qid=457077