On Wed, 9 Sep 1998, Rudderow, Evan wrote:

> Have any of you ever rehosted a Powerhouse application from MPE/Image to
> another platform running an RDBMS?  Or from Image to Allbase?  What kind
> of effort, if any, was involved in re-writing the application to use the
> RDBMS?

Once I worked with an application that abandoned the HP3000 platform and
went to the HP9000.  The good thing was, that it stayed the *same*
application and the application vendor provided the conversion code.

I poured over the code while using it and it boils down to thus:

#1  As a pre-requisite, a Powerhouse data dictionary must reside on the
new machine that accounts for each and every field and dataset in the new
database.  Of course, if the field names and data set names are the same
on the new machine, it makes coding QTP for number #4 below easier.

#2 Either a Quiz or QTP program creates portable subfiles for each and
every data set in the Image database.

#3  The portable subfiles are then "file transferred" to the other
machine.  (How is another topic.)

#4.a  The transferred portable subfiles are then QTP'd into the new
database.

#4.b If you don't have a QTP license on the new machine, (especially if
you plan to abandon Powerhouse entirely), you'll have to write an input
program for each an every field with another language to handle the
portable subfiles.

(Portable subfiles are cool, if the datasets are small enough, you can
read them into a spreadsheet directly, if you download them into a PC as a
".txt" file.)

> Alternatively, have any of you ever written a Powerhouse application
> which used a relational database rather than Image?  Did you have to do
> anything different because of the different database technology?

The Powerhouse dictionary has to be re-written.  The biggest thing I
noticed (or it could have just been the appliation design) was that unique
keys became repeating keys.

Tracy Johnson
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