ok, but the world is bigger then the US, so betetr get used to the format +CC -AC -number -ext, where the plus implies the numbers you have to dial for international calls which you can ommit if you make an national call, CC is the country code, AC the Area code and the number is the number itself and ext an optional extension.
If you apply that scheme you don't have to redefine your DB, modify your .ini sections or worst case to rewrite your code all times you have people from other countries. And US and CAnada schemes might be pretty similar but they are not equal, so better take an open format.
You might also consider to include something alike a code you have to dial before the area code if you make a national call, eg. +CC -(n)AC -number -ext.

Have a nice day
All decision is left to your taste