FIX: DAO Oracle and the NUMBER Datatype

ID: Q180193

The information in this article applies to:

Microsoft Visual Basic Enterprise Edition for Windows, versions 5.0, 6.0
Microsoft ODBC for Oracle (Build 2.573.4202), version 2.5
Microsoft Data Access Components version 2.1 SP2

SYMPTOMS

When using DAO/Jet to access an Oracle database, you get either blank rows back in a grid or rows filled with #DEFINE (when using Access).

CAUSE

This behavior is caused by DAO having a problem determining the datatype for Oracle columns defined as NUMBER.

RESOLUTION

This behavior is only exhibited when the Oracle columns have been defined as NUMBER. If you define the columns as NUMBER(38,0), which is the equivalent of just NUMBER, everything works as expected. When you use DAO/Jet to access an Oracle database, you need to specify the size (total digits) and precision for table columns of type NUMBER.

STATUS

This problem does not occur in MDAC 2.1 SP 2.

The most current MDAC components can be installed from:

http://www.microsoft.com/data

MORE INFORMATION

This problem was identified using Visual Basic 5.0 Enterprise edition, MDAC 1.5 (see the REFERENCES section below), and Oracle 7.3. You may see different behavior with different versions of these components. Following is an example of what will work and what will fail when creating an Oracle table that will be accessed by DAO/Jet.

This Oracle table definition will fail:


      CREATE TABLE daotest (item_number NUMBER PRIMARY KEY,
                            depot_number NUMBER);

This Oracle table definition will work:


      CREATE TABLE daotest (item_number NUMBER(38,0) PRIMARY KEY,
                            depot_number NUMBER(38,0));

If you are using Access, the first example will fill your grid with #DELETE. If you are using Visual Basic/DAO, your grid will show the correct number of rows but they won't contain any data. You can still insert records but you never get the correct display.

REFERENCES

ORACLE: The Complete Reference by George Koch and Kevin Loney

For additional information, please see the following article in the Microsoft Knowledge Base:

Q175018 : HOWTO: Acquire and Install the Microsoft Oracle ODBC Driver

Additional query words: Jet Oracle grid #Define

Keywords : kbDAO kbDriver kbVBp kbVBp500 kbVBp600 kbGrpVBDB kbGrpMDAC kbDSupport
Version : WINDOWS:2.1 SP2,2.5,5.0,6.0
Platform : WINDOWS
Issue type : kbbug