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Preventing Duplicate Entries

Preventing Duplicate Entries

2004-03-21       - By Jim Richardson

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On Sun, Mar 21, 2004 at 07:24:48PM -0800, Axel IS Main wrote:
>I have a php app that updates an ever growing table with new
>information on a regular basis. Very often the information is
>duplicated. I 'm currently handling this by checking the table for
>duplicate values every time I go to add new data. As you can imagine,
>as the table grows it takes longer and longer for this to happen, and
>the process gets slower and slower. In order to speed things up I 'm
>wondering of it might not be a good idea to not allow duplication in a
>given field. The question is, if there is a duplicate, how will MySQL
>react? And what 's the best way to manage that reaction? Also, will this
>actually be faster than doing it the way I 'm doing it now?
>


Perhaps you could hash all the field values into a single 32bit value,
then check for that value in the hash field. You might get a false
positive, but they will be few and far between.

--
Jim Richardson http://www.eskimo.com/~warlock
The race isn 't always to the swift, nor the battle to the strong,
But it 's the safest way to bet.