Why should I limit the column length in MySQL?

If you're sure you will not exceed the numer 9999 you should limit the column int(4). But I was wondering:

• WH开发者_StackOverflow社区Y? What is the advantage?
• And is a tinyint(4) better than an int(4)?

Thanks!

The limit is not used to limit anything, except when ZEROFILL is in play.

Reference: http://alexander.kirk.at/2007/08/24/what-does-size-in-intsize-of-mysql-mean/