Better to store phone in three fields or as one? - php

Question

I am struggling with the decision to separate phone numbers stored in a MySQL database.
One school of thought is to break out the phone as:
area code (123)
prefix (123)
suffix (1234)
Another is to simply place the file in a single field with whatever formatting deemed appropriate:
123456789
[phone]
123-456-7890
My initial reason for thinking the first would be better is in terms of being able to quickly and easily gather statistical data based on the phone numbers collected from our members (X number of members have a 123 area code for example).
Is there really a 'right' way to do it? I do realize that paired with PHP I can retrieve and reformat any way I want but I'd like to use best practice.
Thanks for your advice
EDIT
I will only be storing North American phone numbers for the time being

Answer 1

I vote for one field, processing the data as you put it in so that it's in a known format. I've tried both ways, and the one-field approach seems to generate less code overall.

Answer 2

You want to store it in the most efficient way in the DB, precisely because it's so easy to reformat in PHP. Go for the all-numeric field, with no separators (1231231234) since that would be the best way. If you have international phone numbers, add the country code as well. Then in your code you can format it using regular expressions to look however you want it.

Answer 3

I would store phone numbers as strings, not numbers.
Phone numbers are identifiers that happen to use digits.
Phone numbers starting with zero are valid, but may be interpreted as octal by a programming language.
Strip the phone number to only digits and store the extension in a separate field.
This will allow for uniform formatting later.
For US, strip the prepending ’1′ digit (and determine formatting based on length of the string (10 digits for US)).

Answer 4

I'm in the process of building a callcenter application (it manages queues of contact information for a group of distributed callers to contact) and the architecture specified one field, no spaces, dashes, etc. After quite a bit of analysis, I agree it seems the best.
Based on the variability of entry for phone numbers (apostrophes, dots, dashes, and combinations of each) I built a simple function that deals with user entry, stripping down all but the numbers themselves, and also a "rebuilder" that reformats the raw number into something that's more visually appealing to the user.
Since they've been helpful to me, here's what I've written so far:
public static function cleanPhoneNumbers($input) {
return preg_replace("/[^0-9]/", "", $input);
}
public static function formatPhoneNumbers($phone_number) {
if(strlen($phone_number) == 7) {
return preg_replace("/([0-9]{3})([0-9]{4})/", "$1-$2", $phone_number);
} elseif(strlen($phone_number) == 10) {
return preg_replace("/([0-9]{3})([0-9]{3})([0-9]{4})/", "$1-$2-$3", $phone_number);
} else {
return $phone_number;
}
}
Some caveats: My app is not available for international customers right now (there's a voip application built into it that we don't want to allow to call outside of the US right now) so I've not taken the time to setup for international possibilities. Also, as this is in progress, I will likely return to refactor and bolster these functions later.
I've found one weakness so far that has been a bit of a pain for me. In my app, I have to disallow calls to be made by timezone based on the time of day (for instance, don't allow someone on the West Coast to be called at 6:00am when it's 9:00am in the East) To do that, I have to join a separate area code table to my table with the phone numbers by comparing 3 digit area codes to get the timezone. But I can't simply compare the zip code to my phone number field, because they'd never match. So, I have to deal with additional SQL to get just the first three digits of the number. Not a game-changer, but more work and confusion nonetheless.

Answer 5

Definitely store them in one field as a text string, and only store the numbers. Think of it this way; no matter what the numbers are, its all one telephone number. However, the segmenting of the numbers is dependent on a number of things (locality, how many numbers provided, even personal preference). Easier to store the one and change it later with text manipulation.

Answer 6

I think splitting the number in 3 fields is the best options if you want to use area codes as filters, otherwise, you should only use 1 field.
Remember to use ZEROFILL is you plan on storing them as numbers ;)

Answer 7

it really depends on a couple factors:
is it possible you will have international numbers?
how much area code/city code searching/manipulation will you be doing?
No matter what, I would only store numbers, it's easy enough to format either in MySQL or PHP and add parentheses and dashes.
Unless I was going to do a log of searching by area code, I would just put the entire phone number into a single field since I assume most of the time you would be retrieving the entire phone number anyway.
If it's possible that you will take international numbers in the future:
You might want to add a country field though, that way you won't have to guess what country they are from when dealing with the number.

Answer 8

What you use depends on how you plan to use the data, and where the program will be used.
If you want to efficiently search records by area code, then split out the area code; queries will perform much faster when they're doing simple string comparisons versus string manipulation of the full phone number to get the area code.
HOWEVER, be advised that phone numbers formatted XXX-XXX-XXXX are only found in the US, Canada, and other smaller Caribbean territories that are subject to the NANPA system. Various other world regions (EU, Africa, ASEAN) have very different numbering standards. In such cases, splitting out the equivalent of the "area code" may not make sense. Also, if all you want to do is display a phone number to the user, then just store it as a string.
Whether to store a number with a format or not is mostly personal preference. Storing the raw number allows the formatting to be changed easily; you could go from XXX-XXX-XXXX to (XXX) XXX-XXXX by changing a couple lines of code instead of reformatting the 10 million numbers you already have. Removing special characters from a phone number is also a relatively simple Regex. Storing without formatting will also save you a few bytes per number and allow you to use a fixed-length field (saving further data overhead inherent in varchars). This may be of use in a mobile app where storage is at a premium. However, that 5-terabyte distributed SQL cluster in your server room is probably not gonna notice much difference between a char(10) and a varchar(15). Storing them formatted also speeds up loading the data; you don't have to format it first, just yank it out of the DB and plaster it on the page.