使用varchar或Char对于加密的Salt？

Question

It has always puzzled me with the creation of my Databases. What would be the correct data type for my Encrypted with md5 salt password?

I've been using VarChar; but i've been told to move over to char but never given an explination?

Which also, I know it's not in best practice but i've got my database as Varchar(255) to hold my password; What would also be the best length to have it? because I don't know for certain if md5 always returns the same length string, or it can vary?

Answer 1

You're first question:

VARCHAR

• Trailing white space is preserved. (MySQL 5.0.3+ only.)
• Minimal storage overhead. A 17 character record takes up only 17 characters of space.
• Slower SELECTs when searching this column.

CHAR

• Trailing white space is always removed.
• Every record takes up a fixed amount of space - 19 characters in your case. Your 17 character records will waste two bytes of storage.
• Faster SELECTs when searching this column.

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