SYMPTOMS

No records are returned when a Paradox user tries to search a Paradox database created using the Microsoft Access Export command. This problem occurs only when the criteria specifies fields that are BLANK. (The Paradox BLANK criteria is equivalent to the Microsoft Access NULL criteria.)

CAUSE

When Microsoft Access exports a table to a Paradox database, all fields that are NULL in Microsoft Access are replaced with a space during export to Paradox. This prevents Paradox users from correctly retrieving records based on the Paradox BLANK criteria command.

This problem may also occur if a Microsoft Access .MDB file attaches a Paradox database and the Microsoft Access user deletes the entire contents of a field from the attached Paradox database. Microsoft Access treats the empty field as NULL, while a Paradox user treats the same field as NOT BLANK.

STATUS

Microsoft has confirmed this to be a problem in Microsoft Access version 1.0. This problem no longer occurs in Microsoft Access 1.1.

MORE INFORMATION

Steps to Reproduce Problem

1. Open the sample database NWIND.MDB.
2. From the File menu, choose Export.
3. In the Export dialog box, select the Paradox 3.X file format and the Customers table. Name the file CUSTOMER.DB.
4. Open Paradox 3.5 and create a new query, using graphical query by example (QBE) on the exported CUSTOMER.DB file.
5. Using the F6 key, check the Customer ID and Region fields in QBE.
6. Add the criteria BLANK to the Region field.
7. Press F2 to execute the query. Zero records are returned to the Paradox Answer table.
8. Change the criteria of the Region field to NOT BLANK, then press F2. Note that all the records are returned.