Synopsis: Multi-column Attributes

We may all have the experience of using or creating tables to store people’s contact information. Such tables often have common columns, such as the contact’s name, salutation, address, and sometimes company name.

Phone numbers are a little trickier. People use multiple numbers: a home number, a work number, a fax number, and a mobile number. In the contact information table, it’s easy to store these in four separate columns.

But what about additional numbers? The person’s assistant, second mobile phone, or field office have distinct phone numbers, and there could be other unforeseen categories. We could create more columns for the less common cases, but that really compromises the table’s outlook ...