Re: RE: Re: query on PF

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You are correct, it is not possible.  Actually anything is possible, given
enough time and money.  What you could do is put a trigger on the file and
not allow any new duplicates.  But I'd strongly lean towards cleaning up
the old duplicates.

Sample way to find duplicates:

Entire table:
MYKEY       MYDATA
A           hi
A           bye
B           guten tag

Find them:
Select RRN(B),b.mykey From rob/murali B, rob/murali C
    Where B.mykey = C.mykey and RRN(B) > RRN(C)
RRN ( B )   MYKEY
        2   A

Blast them:
Delete From rob/murali A
    Where RRN(A) in
     (Select RRN(B) From rob/murali B, rob/murali C
        Where B.mykey = C.mykey and RRN(B) > RRN(C))
1 rows deleted from MURALI in ROB.

Prove it:
select * from rob/murali
MYKEY       MYDATA
A           hi
B           guten tag

Rob Berendt
--
"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety."
Benjamin Franklin




"MURALI DHAR" <nmuralidhar@rediffmail.com>
Sent by: rpg400-l-admin@midrange.com
10/15/2002 12:14 AM
Please respond to rpg400-l


        To:     joepluta@PlutaBrothers.com
        cc:
        Fax to:
        Subject:        Re: RE: Re: query on PF


yes u r correct....I already entered duplicate records....i dont
like to go bak and delete them..from now onwards i want to enter
only unique records..Iam trying to find some solution to this...i
think its nt possible...T
Thanks&Best Regards,
Murali
On Tue, 15 Oct 2002 Joe Pluta wrote :
> > From: MURALI DHAR
> >
> > I have duplicate records in it...Can i now change it to
>unique
> > PF....?
>
>Murali, think about what you are asking.  You are asking if you
>can take a
>file that has duplicate keys and make it have unique keys.  Only
>one of two
>options exist:
>
>1. The operating system deletes records with duplicate keys
>2. The operating system keeps the duplicate keys
>
>Option one would destroy data.  I doubt this is what you want.
>Option two
>is a contradiction, because the keys in the file would not be
>unique.
>
>So, common sense should indicate that the answer is no, you
>cannot convert a
>file with duplicate keys to unique key access, without first
>removing the
>duplicate keys.
>
>If you choose to ignore common sense, you could simply try it
>yourself, like
>I did, and find that you'll get a CF4012 if you try to access a
>unique view
>over a file with duplicate keys.  I did this by entering data
>into a file,
>then changing the file to UNIQUE.  When I went to access the file
>with
>UPDDTA I could not access it.
>
>On the other hand, I was able to access the data in this mangled
>file using
>SQL.  So the answer to your problem might be simply to use SQL.
>
>Joe
>
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