Addresses. These are always a little tricky.
In theory, they might be repeating. But just how many addresses overlap?
If you made a lookup table, would a store, vendor, and customer share the same address?
However, it can make sense to have a lookup table for postal/zip codes.
Comments. Are you thinking of multiple comments over time?
Or just one for the customer record?
If just one comment on the customer record, I would use the NVarchar datatype in the customer table.
NVARCHAR column can store up to 4000 characters (2 bytes per unicode character)
The data will be compressed. No big increase in space.
But if you needed a field for an object for say a picture, that I would create into a separate table.
And only insert a record if there was a picture to insert.
See some writing I did on a similar subject at:http://rodgersnotes.wordpress.com/2...gle-table/
I've compiled many other DB Design Mistakes to Avoid at:http://rodgersnotes.wordpress.com/c...-to-avoid/
Hope they help.