Agnes,
After a bit more thought, base 36 probably would be better. See http://en.wikipedia.org/wiki/Base_36 If you scrolled down there is some code examples.

Have a good day.

>Neil
>Okay,
>
>and how do I that?
>
>Convert to base 26?
>Agnes
>
>>Hi,
>> Since the data is a mixture of numeric and alpha chars, maybe convert the data to base 26 fully padded and store in the indexes. All subsequent searches will have to be done at base 26.
>>
>>