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

Post code is not a number: it's a code or identifier. The same applies to phone numbers.

Number of files in a torrent is an integer.

Not least, in this case you can create a CHECK CONSTRAINT LIKE '[09][09][09][09]' to keep data correct at the database level.