Integer vs String in database

Question

When defining datatypes in a database, I have always had a problem with choosing whether to use integers or strings to store certain \'numerical\' data.

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Answer 1

It is also good to remember that not all postal codes in all counrties are numbers only. Just because you don't have any addreses in Canada right now doesn't mean you won't have any. I've always gone by the rule, if you want to do math calculations store it in a numeric type, if it is just a code (postalcodes, phones, SSN, partnumber, etc) then I store it as a string. What you want to avoid is any unnecessary casting of the data into another format every time you call it up (for instance code to add the leading zeros if you store the postal code as a number or code to convert a string to a number for calulations). These can be expensive operations if you need to do them repeatedly, espcially when the tables are large and you end up having to do the conversion in the where clause. It is far better to store the data the way you need to use it.