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Message
From
31/01/2005 04:46:23
 
 
To
31/01/2005 01:31:18
General information
Forum:
Visual FoxPro
Category:
Other
Title:
Re: Index
Miscellaneous
Thread ID:
00982167
Message ID:
00982184
Views:
28
>Hi All,
>
>I would like to know whether is there a way to index a table on 2 coulmns, Both are character fields. The First column has to be descending while the 2nd Column has to be ascending.
>
>Any answers,
>Thanks,
>JD.


As said, everything is possible
&& simple solution
&& use a view

create sql view ViewOnTablexx as ;
    select ..... ;
        from Tablexx ;
        order by Fieldx desc, Fieldy asce
Another possibility
function CharBitNot(s)
    return chrtran(m.s, chr(0)+chr(1)+chr(2).....+chr(255), chr(255)+chr(254)....+chr(1)+chr(0))
endfunc

select Table
index on CharBitNot(Fieldx) + Fieldy tag pp

&& performancewise it would be best to build the chrtran() arg2 and arg3
&& in the init of your program, you could
=_screen.AddProperty(BitNotCharFrom, chr(0)+chr(1)+chr(2).....+chr(255))
=_screen.AddProperty(BitNotCharTo, chr(255)+chr(254)....+chr(1)+chr(0))
&& or use a loop to build them

select Table
index on chrtran(Fieldx, m._screen.BitNotCharFrom, m._screen.BitNotCharTo) + Fieldy tag pp
There may be other possibilities
Gregory
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