Qualifiers 

Just as a taxonomy table has attributes, additional fields of information for the category that you assign to a product, a qualified table has qualifiers, additional fields of information for each qualified table record that you assign to a product. But unlike a taxonomy table, which allows you to assign attributes to categories on a category-by category basis, a qualified table uses the same set of qualifiers for all qualified table records.

Depending upon the context, a particular qualifier can be thought of as an extension to: (1) the main table record (for example, prices); (2) the qualified table record (for example, vehicle specifications); or (3) the link itself between the main and qualified table record (for example, jobs).

Qualified table fields and qualifiers are interchangeable, but with an effect on the number of qualified table records and on search efficiency and performance. Specifically, each field increases the number of qualified table records, which slows down the system but makes the qualified lookup field itself more searchable.

Assigning attributes to categories on a category-by-category basis in a taxonomy table is a good idea because the number of category records is relatively small and the number of attributes is relatively large. By contrast, assigning qualifiers to qualified table records on a record-by-record basis in a qualified table would be cumbersome because the number of qualified table records is relatively large and the number of qualifiers is relatively small.