Re: Export and Import Utility

Rod Fergusson <rod.fergusson_at_canada.attgis.com> wrote:
>

>
> From the scenario that you have painted...it looks like you are
> hurting for disk space... It would be helpful to know whether
> the USER will be repeatedly archiving files to the tape...or
> will they be only exporting one file. If there are going to be
> multiple exports on a tape..you are going to run into problems
> with identifying which export file to retrieve for an
> import..and possibly running out of space on the tape...what is
> going to happen if they have to mount additional tape volumes?
>
>
> If it is only one file at a time...I would launch a VMS command
> procedure from within your application..perform the export to
> disk...(it's faster)...then copy the file to the tape...delete
> the disk file..and REWIND the tape...within the same command
> procedure..that way...it's ready for a retrieval. LAUNCH THIS
> PROCEDURE IN BATCH...
>
>
> I don't see why you can't pseudo use the tape like a disk...as
> long as you are aware that you have to rewind the tape in order
> to read back off of it. I don't think it's is a solid solution
> to a production application problem...but I don't know what the
> whole situation is.
>
> I suppose it is also possible to implement this solution if
> they were going to be doing multiple exports to the same
> tape...but the solution will get a bit trickier because you
> will have to keep track of the names and savesets of the
> different exports. I would create a database table to contain
> and track these.
>
> Hope this helps.... Sandra Fergusson
>

Sandra:

Thanks for the reply..

A little more detail may help. We will be logging messages (data) into multiple tables as they are received from a remote system via a DECNET type protocol.

The user, as stated in our requirements document, must have an on-line option to save any of the messages in the DB tables to tape. We really don't have a disk space problem, just this requirement to adhere to. I guess a more important question is, and I think I may know the answer, can only certain rows of tables be exported from tables or does the whole table have to be exported ? If I remember correctly, the whole table. In that case, if the user wants to save messages from 45 different tables besd on a time/date key to tape, the entire table would have to be exported. Doesn't sound good considering that each message is only a row in a table.

The user then must be able to restore the messages at any time so they can be viewed in a Form.

Thanks again

Stan Received on Mon Jun 12 1995 - 00:00:00 CEST