Re: DDF Maker keeping old structure after structure change

Steven Blank


It has to do with the way that uniPaaS stores metadata in DataSources.xml. Specifically, uniPaaS maintains a redundant copy of certain values in the source xml, in an element named <_FieldPhysical /> (see below), and DDF Maker looks at this permanent, backup copy to obtain the table's record-layout.

As a failsafe, the Studio does not update this permanent, backup copy in the xml source until it successfully converts any existing data file – keyword: EXISTING.

The trick is simply to rename (or repoint) the underlying data file, make the structural change, then rename the file back again.

Or clone the original data file and offer up the [empty] clone as a sacrifice.

Steve Blank

On 6/1/2020 2:08 PM, Keith Canniff wrote:



Can you explain why? I’ve had times where I’m just changes the Magic picture but the internal storage format will stay the same (picture from 6.1 to 6.2), yet Studio will want to do a conversion, which I cancel. Wouldn’t care if it were a small file, but when you’re dealing with 10 million rows, it becomes a big deal.




From: <> On Behalf Of Steven Blank
Sent: Monday, June 1, 2020 4:51 PM
Subject: Re: [magicu-l] DDF Maker keeping old structure after structure change



When you make a change to a table in the Data Sources Repository, DDF Maker will not "see" the change UNLESS you allow the Studio to perform a conversion on the modified data source.

The reason why you did not allow the Studio to convert the data source is irrelevant.

You must allow the Studio to convert the Data Source whenever you make such a change.

Steve Blank


On 6/1/2020 1:28 PM, Harry Techie wrote:

Hi All

I'm using the DDF maker in xpa 3.1, it happens from time to time when i do a change in a file structure and i rerun the DDF Maker tool, it generates the DDF files with the old structure, or pervasive is keeping the old structure even though the DDF files are replaced.
I'm physically moving the original DDF files to a backup folder and then generating the new DDFs and when i open the files in pervasive control center it still has the old structure.
I know that pervasive is pointing to the new ddf files, because i have some VIEWs in the database, and when i replace the DDFs i always have to regenerate the VIEWs.

Steve or anyone has an idea how to overcome this?

Hershel Teitelbaum


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