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Creating Indexes on Number Columns

 
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Hi,
is there any performance overhead creating indexes on a table columns, whose data type is other than number or interger? i mean if we have a table Emp with the following structure and assume that eno, ename both will only accept unique values. in this case , what is the recommended way to create index? is it on eno or ename? i read that indexes on numbers will have better performance over the indexes, which are created on characters. could any body please explain the reason behind this.
Thanks.
--Deepika
 
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Deepika,
The fastest index is the one that is used the most. Do you have more queries/joins by number or name? I would imagine number making it the best choice of an index.
 
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