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Q169154: PRB: Error "OLE Object is Invalid or Corrupt" on Empty Gen Field

Article: Q169154
Product(s): Microsoft FoxPro
Version(s): WINDOWS:5.0,5.0a,6.0
Operating System(s): 
Keyword(s): kbcode kberrmsg kbvfp kbvfp500 kbvfp500a kbvfp600
Last Modified: 11-DEC-1999

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, versions 5.0, 5.0a, 6.0 
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SYMPTOMS
========

When upsizing FoxPro data to an SQL server, empty general field records may
cause an error when browsing the resulting SQL table.

CAUSE
=====

This is caused by an empty general field being upsized as an hex 20 (which is a
space character). FoxPro expects to see binary data in the general field rather
than an ASCII character.

RESOLUTION
==========

The problem can be avoided by setting the General field to accept NULL values.
This can be done in either of two methods when creating the table:
programmatically or visually.

To programmatically allow a NULL value, use the NULL keyword when creating the
field in the table.

     * The following line of code creates a table called 'gendata'. The
     * General field in the table, 'gfield' accepts NULL values.

     CREATE TABLE gendata (gfield G NULL)

To set the field to accept NULL values using the visual interface, place a check
mark in the NULL column for the field, in the Table Designer dialog box.

STATUS
======

Microsoft is researching this problem and will post new information here in the
Microsoft Knowledge Base as it becomes available.

MORE INFORMATION
================

Steps to Reproduce Behavior
---------------------------

There are three parts in setting up this example: Part 1 is to create a small
table with empty general records to be used in the Upsize Wizard. Part 2 is to
upsize the data to an SQL server. Part 3 is to create a remote view of the SQL
data to observe the error.

Part 1 - Create a table with empty general field records:

Save the following code to a file called Creatabl.prg:

     *** Begin code ***
     CLOSE ALL
     CREATE DATABASE test
     CREATE TABLE gendata (gfield G)
     APPEND BLANK
     APPEND BLANK
     APPEND BLANK
     GO 1
     APPEND GENERAL gfield FROM c:\windows\waves.bmp
     GO 3
     APPEND GENERAL gfield FROM c:\windows\tiles.bmp
     *** End code ***

Part 2 - Upsize the data to an SQL server:

1. From the Visual FoxPro Tools menu, select Wizards and click Upsizing.

2. In the Wizard Selection dialog box, click SQL Server Upsizing Wizard and
  click OK.

3. In Step 1, select the Test database, and click Next.

4. In Step 2, select the SQL data source to upsize to, and click the Next. NOTE:
  At this point, a login screen may come up. Login into the SQL data source to
  continue.

5. In Step 3, move the Gendata table to the Selected Tables pane, and click
  Next.

6. In Step 4, select Map Field Data Types, and click Next to continue.

7. In Step 5, select the target database to upsize the data to (this could be an
  existing or new database). Then, click Next. NOTE: If an existing database is
  chosen, Steps 5 and Steps 6 will be bypassed. Otherwise, if this is a new
  database, the following steps will be performed.

   - In Step 6, set the appropriate database properties, and click Next.

   - In Step 7, set the appropriate log properties, and click OK.

  These last two steps complete the steps necessary when setting up a new
  database on the SQL server.

8. In Step 8, set the upsizing options. In this test, all of the check boxes can
  be cleared. Then, click Next.

9. In Step 9, click Finish to upsize the data to the SQL server.

Part 3 - Create a remote view of the upsized-SQL data:

1. Open the Test database if it's not already open by entering the following
  command in the Visual FoxPro Command window:

        OPEN DATABASE test

2. From the Visual FoxPro File menu, select New and click Remote View. Click
  Wizard to bring up the Remote View Wizard.

3. In Step 1, select the data source where the upsized data exists, and click
  Next. NOTE: At this point, a login screen may come up. Login into the SQL
  data source to continue.

4. In Step 2, move "gfield" from the "gendata" table to the Selected Fields
  pane, and click Finish to bypass Steps 3, 4, and 5, which are not necessary
  in this example.

5. In Step 6, select "Save remote view and browse", and click Finish. NOTE: Once
  the Remote View Browse window appears, open "gfield" for record 2 and observe
  the "OLE Object is Invalid or Corrupt" error message.

Additional query words:

======================================================================
Keywords          : kbcode kberrmsg kbvfp kbvfp500 kbvfp500a kbvfp600 
Technology        : kbVFPsearch kbAudDeveloper kbVFP500 kbVFP600 kbVFP500a
Version           : WINDOWS:5.0,5.0a,6.0
Issue type        : kbprb

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