Best data type for indexing??

Iv'e been searching through my Oracle manuals for hours and I can't come up with a good answer. What is the best (i.e. fastest) data type to use for an index, if it can be any type. I would think a raw the size of a word on the target machine, but it's not portable. So I'm assuming a number would be the next best. Is this a valid assumption. On a side note, if no precision is specified on a number, does Oracle store the maximum number of bytes for that number? (i.e. if the number is 1 does it take up a byte for the mantissa and a byte for the number, or does it take a byte for the mantissa and however many bytes it takes to store 38 digits)

   Thanx,

      Chad

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 ) Chad A.Brockman           -                                 ( 


(  VertiComp, Inc.           -   I'm just an OS/2 junkie!!      )


 ) chadb_at_sugar.NeoSoft.com   -                                 (