Is it better to store telephone numbers in some canonical format or “as entered”?

Question

Storing a telehone number in some kind of canonical format has several advantages from a programmers point of view, but it might confuse the user, if sudde

Answer 1

Separation of Duties - Content and Rendering

Store the number in a canonical format and the display format mask.

Gains:

• Canonical format for consistency, quality, and ease of analysis
• Format retained from end-user perspective
• Format re-usable to display other phone numbers in end-user preferred method
• Other format masks can be used to display canonical number to other users with a need to see the phone number

Pains:

• Parsing the phone number to the canonical format
• Parsing out the display format mask (not too painful in combination with above bullet)
• Storing the display format as an end-user preference