>The following is the Select statement for a view :
>
>SELECT Ptinvent.brand, Ptinvent.partno, Ptinvent.descrip,;
> Ptinvent.rating, Ptinvent.utqg, Ptinvent.price1, Ptinvent.onhand,;
> Ptinvent.committed, Ptinvent.milwar, Ptinvent.saprice,;
> Ptinvent.warehouse, Ptinvent.cost, ; Ptinvent.taxind,Ptinvent.acctrevn,;
> Ptinvent.acctrevnt, Ptinvent.acctcogs, Ptinvent.acctinvt,;
> Ptinvent.groupcd, Ptinvent.reqreas, Ptinvent.olform, Ptinvent.pcom,;
> Ptinvent.fet, Ptinvent.price2, Ptinvent.price3, Ptinvent.wpartno;
> FROM vitdata!ptinvent;
> WHERE Ptinvent.twidth = ?vWidth;
> AND Ptinvent.tratio = ?vRatio;
> AND Ptinvent.rim = ?vRim;
> ORDER BY Ptinvent.warehouse
>
>The table ( ptinvent ), currently has an index ( twidth + tratio + rim )
>

This index is not optimizable in your current query. It's not being used at all.

>Would I get better performance with seperate indexes on each of the three fields in the ptinvent table ?

Yes.

>Can the view statement be changed for better performance after the WHERE
>Ex: WHERE ( Ptinvent.twidth + Ptinvent.tratio + Ptinvent.rim ) = ;
> ?vParameter

With the current index, yes that would help. Is this view the only place that you filter on these fields? If so then this would work fine, otherwise, I recommend separate indexes.