What is an index in MySQL?

Posted by Eric on Stack Overflow See other posts from Stack Overflow or by Eric
Published on 2010-04-08T12:25:52Z Indexed on 2010/04/08 12:33 UTC
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mysql

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database

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database-design

http://i.imgur.com/JdsUK.jpg

I created a table like the picture above. What are the "Indexes"? primary key? unique? It works well without setting indexes.. What do they do? why do I need them?

Also, I set all String fields to TEXT because I didn't know how many characters I need. Is this a good idea? I don't see any difference.

Thanks!

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