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Database tables not appearing in Pervasive

Posted on 2006-11-30
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Last Modified: 2013-12-25
I am not sure if anyone is familiar with MPM, but it's software used for project management which utilizes btrieve tables. I am doing some testing on connecting to the databases through Pervasive, but I'm having a problem with some tables appearing for a particular database.
In MPM, I copied one of my projects. This creates a new folder with the btrieve data files, which are supposed to be populated with the same data as the old project. The new project folder does show all of the files. I went into Pervasive to Maintain Named Database and add a database that points to these particular files, choosing the option to create the DDF files since they do not exist. So the DDF files get created and the database name is added in Pervasive. Then I click on Tables under the new database and the tables that should be in there aren't. I'm not sure what the problem is. The same files in the new folder are the same as in the old folder, and the old database shows the correct tables. Can anyone help?
Thanks~
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Question by:jenndo
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Bill Bach earned 500 total points
ID: 18050244
I think you already indicated the answer.  "The DDF files get created" -- when a new set of DDF's is created, it is devoid of any table information.  Normally, you would use CREATE TABLE statements to build the DDF data structures.

Luckily, you have a solution, too.  The old database already works, and it has fully-populated DDF's.  Simply copy the DDF's from the old directory into the new directory, and then reopen the database.  Check the X$Files table to be sure that there are no hardcoded paths in the DDF's, and as long as there are only simple file names, your newly-copied DDF's will now reference your new data.

For a full explanation of how DDF's and the MPM Btrieve files work together, check out the white paper at www.goldstarsoftware.com/press.asp -- look for the paper on ODBC Access for Btrieve Files.  This should clear up any remaining confusion.
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Author Comment

by:jenndo
ID: 18053240
Wow! That was an excellent answer and EXCELLENT reference. Thanks bunches! A++++++++++++++++++++++++  :)
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Author Comment

by:jenndo
ID: 18053975
umm.... I am unable to open X$File. It gives me the error "Unable to open table: X$File". This happens even with my old project that actually works fine. Any ideas on what the problem is and how I can open the file? I'm trying to open it in Pervasive. Do I have to open it some other way?
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Author Comment

by:jenndo
ID: 18054006
Btw, I'm not sure if you can award more points for this question or not since one answer was selected, but if my last question is answered I will open a new question and award the points.
Thanks!
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LVL 28

Expert Comment

by:Bill Bach
ID: 18054078
I don't worry about points -- this is about providing solutions.

If you are unable to open the X$File table, then this indicates that the DDF's themselves may be damaged, or otherwise incorrectly built by the database developer.  X$File is a system table that contains information on finding all of the other tables -- without it, nothing else should work.  There must be some sort of anomaly in the way this DDF set was constructed.

Here is one way that might help:  Create a new database in an empty directory.  This will create an empty set of DDF's, but one which is properly structured (and X$File will be working).  Then, from the Pervasive Maintenance Tool, do a Data/Copy operation to move all the records from one set of DDF's to another.  (You'll need to do each DDF file separately.)  The owner name will be required when you do this -- use "..SC...." when prompted.  Try out the new database & see what happens -- it may fix it, but it may also mangle the DDF's, depending on lots of different factors (of how they were built originally).  

Be sure to keep a backup of your older DDF's while you are experimenting with this.  Beyond this, the self-help options are limited, and a formal rebuild of the DDF's may be needed (by a professional).
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