>>>>>is possible to create a calculated field in a VFP table?
>>>>You need to create a view on the table and use that view
>>>
>>>Thank you.
>>>I need an index on computed field :(
>>
>>You can index a view -
>>
>>

>>&& form load 
>>use viewname in 0 nodata
>>select viewname
>>index on fieldname tag xxx
>>
>>&& later 
>>Viewparam1 = ...
>>
>>=Requery('viewname')
>>

>
>it is persistent ?
>Every update/delete/insert on table refresh view index ?

Nope.