> If I am reading down a chain and updating the values for that chain's
> search item, what happens to the chain information?  For instance, this
> program does a chained read by a certain value, and replaces the value for
> that search item with zeroes.  Can I do:
>
> DBFIND
>
> DBGET (chain forward)
>
> DBUPDATE (with new value)
>
> Go back to DBGET until end of chain is reached
>
> Or will the program "lose its place" on the chain because of the changing
> search item values?  If so, then I suppose I will have to save the value of
> the next record on the chain and get that record by address, instead of by
> chained read, so the processing logic would look like this:
>
> DBFIND
>
> DBGET (chain forward)
>
> Save next record address
>
> DBUPDATE (with new value)
>
> DBGET (by direct record address)
>
> Go back to the "Save" until there is no next record.
>
> On a related note, if I am reading down chain A and changing values for
> chain B's search item, what happens to the chain information?  Can I do
> what I outlined above in the first logic example, or will I need to keep
> track of the chain information in the program, as in the second example?
>
> As always, any and all help is appreciated.
>
> Jim Phillips                            Manager of Information Systems
> E-Mail: [log in to unmask]      Therm-O-Link, Inc.
> Phone: (330) 527-2124                   P. O. Box 285
>   Fax: (330) 527-2123                   Garrettsville, Ohio  44231

 Hi,

When you do DBUPDATE (with CIUPDATE), TurboIMAGE internally handles the
chains. It internally does a re-read to establish the current updated entry
and the chain. You can use the steps as in your first example without any
problem. Also refer Chapter-4 of TurboIMAGE manual, sub-heading 'Updating Key,
Search and Sort items' for a discussion of appropriate dbopen, dbcontrols etc.

Hope this helps

--
Regards,
Vikram

Vikram Kumar B T,

Hewlett Packard India Software Operations Ltd

29 Cunningham Road, Bangalore 560 052, India