PRB: ODBC - Call Failed Error When Appending Record in Access

• Microsoft Visual FoxPro ODBC Driver, version 1.0

SYMPTOMS

If you attach a FoxPro table to a Microsoft Access version 7.0 database, and do not fill all the fields in a new record, the following errors are displayed when you move off the record:

      ODBC- Call Fail

      Field <field_name> does not accept NULL values

CAUSE

Moving the record pointer commits the data to the table. The data contains NULL values. However, the structure of the Visual FoxPro table does not allow NULL values, and changes cannot be saved to the Visual FoxPro table.

The "AllowZero Length" property of a field in an Access table controls the default value of fields. When it is set to No, the default in Access version 7.0, fields are initialized to NULL. Therefore, if you append a new record and do not fill all of the fields, some fields will have a NULL value. This is causing the error message because the linked table does not allow NULL values.

WORKAROUND

You can ensure that the fields in the Visual FoxPro table accept NULL values by checking the NULL setting in the Visual FoxPro Table Designer. Use the following step-by-step procedure to achieve this:

1. Start Visual FoxPro and open the database that contains the table.

2. Right click the table and select Modify.

3. When the Table Designer is opened, select the NULL check box for every field.

STATUS

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

MORE INFORMATION

Steps to Reproduce Behavior

1. Using the Microsoft Visual FoxPro ODBC driver, set a datasource to the Tastrade database located in the Samples\Mainsamp directory off the main Visual FoxPro directory.

2. Start Microsoft Access version 7.0.

3. Right click and select "Link Tables" from the shortcut menu.

4. Select ODBC Databases.

5. Click the Data source to Tastrade.dbc.

6. Open the Category table.

7. In the Datasheet view, position the cursor to the empty record.

8. Enter information in the fields, but do not enter anything in the OLE Object field.

9. Move the cursor off the record. The ODBC-Call Failed error message is displayed, followed by the error "Field PICTURE_FILE does not accept null values (#581)."