[Cialug] mysql index/unique

[carl-olsen at mchsi.com]

Unique index means no duplicates.  A regular index allows duplicates.  I'm not sure I understand indexing, but I think it keeps a separate table with only that column(s) for faster lookups.  It appear that you can also specify a column with unique values that is not indexed.

Carl

-------------- Original message from Barry Von Ahsen <barry at vonahsen.com>: -------------- 


> when I try to make a column unique then index it in phpMyAdmin, it does 
> it, but complains that you shouldn't use unique and index on the same 
> field. I've checked the mysql manual for indexes[1], and it doesn't say 
> anything good or bad (but it doesn't say much at all). 
> 
> is this bad/good/indifferent? does unique imply index? 
> 
> this is for mysql 4.1 
> 
> -barry 
> 
> [1] http://dev.mysql.com/doc/refman/4.1/en/mysql-indexes.html 
> 
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