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Character column Index

Posted on 2002-06-14
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Last Modified: 2013-12-03
Hello experts!!!!

Can anyone tell me if an index applied to a character column is slower than other applied to a numeric column?

Thanks.
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Question by:dbroosv
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by:yoren
ID: 7079756
For most applications, no. Yes, character comparisons are generally slower than integer comparisons, but other factors such as how your tables are designed and the options you use to create the index will affect performance far more.

Basically, if you have numeric data, put it into a number column. If you have character data, put it into a character column.
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Guy Hengel [angelIII / a3] earned 100 total points
ID: 7080288
character column -> index performance

The index performance depends on the size of the column, not on the datatype as such. Of course, a column with 1 caracter will be as performant as a numerical column on 1 byte, because they will have as many index entries in one data page. If you have a column on 2 caracters, only half of the index entries will be on 1 page, thus the index will need 2x the index pages. For the index search this can mean max 1 index page more to read, depending on the implementation, and this index page read can be the performance loss.

CHeers
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