The information in this article applies to:
SUMMARYDAO is a COM wrapper around the Jet Engine, which is used by Microsoft Access, Excel, Project, Visual Basic, and the Microsoft Foundation Classes (among others). It can be confusing which version of Jet you are using because so many applications may distribute Jet onto your machine. The tables and explanations in this article are intended to help you identify the version and components of Jet that you are using for the given application. MORE INFORMATION
This table displays which version of Jet is shipped with each of the
following products.
Compatibility Among VersionsWith each new version of Microsoft Jet, enhancements in functionality and changes to the structure of the database file cause problems with backward compatibility. Wherever possible, efforts have been made to ensure an easy migration path among versions. However, incompatibilities do exist. The following table illustrates how you can use database files and objects among different versions of Microsoft Jet.
A "Y" indicates that you can use the database without conversion; "N" indicates that you cannot use or convert the database. With DAO code, you can open any version of any database up to the same version of Microsoft Jet. Microsoft Access is an exception to this rule because it can open only those databases with the same version as itself. However, it can link to tables with the same or earlier version. In other words, if you upgrade to Microsoft Jet 3.0, you will still be able to read version 2.x databases. There is no version 2.5 or 3.5 of an .mdb file (just 2.0 and 3.0), which are common to the x.0 and x.5 versions of Jet. Jet 2.0 and Jet 2.5 use identical database formats in every aspect. Jet 2.0 can read databases created with Jet 2.5. Microsoft Jet 3.5 databases have the same structure as Jet 3.0. Microsoft Jet 3.0 can read data from Microsoft Jet 3.5 tables. The main limitation here is that Microsoft Jet 3.5 may support additional properties on the database object that aren't recognized or taken advantage of by Microsoft Jet 3.0, but there aren't any data incompatibilities. Notice that Visual Basic 3.0 is capable of using three different versions of Jet each requiring a separate set of dynamic link libraries (DLLs). This can cause problems when your Visual Basic application expects to use Jet 2.0 for example, and then you install another Visual Basic application using an earlier version of Jet on the same system that replaces some of the version 2.0 DLLs with version 1.1. Typically the problem DLL in this situation is Vbdb300.dll because it determines which version of the Jet engine will be used. The following table should help you solve any version conflicts, and help you identify the version of Jet you are using. You may use the Wps.exe utility shipped with Visual Basic to find out which version of Jet you currently have loaded in memory. Wps.exe is located in the \VB\CDK directory of Visual Basic 3.0 Professional, and in \TOOLS\PSS directory of the Visual Basic 4.0 CD. Pay special attention to the version information obtained from File Manager (File, Properties) in Visual Basic 3.0, and Microsoft System Info. in Visual Basic 4.0 32-bit. The following files are required by Visual Basic to use the Jet Database Engine:
With Jet 3.5x, there have been multiple releases. The following table indicates which version of Jet applies to a given product:
REFERENCES
"Microsoft Jet Database Engine Programmer's Guide 2nd Edition," by Dan
Haught and Jim Ferguson, Microsoft Press, 1997, ISBN 1-57231-342-0
Q113951 HOWTO: Obtain/Distribute the Compatibility Layer in VB 3.0You can find information about how to download the Jet 3.51 patch in the following Knowledge Base Article: Q172733 ACC97: Updated Version of Microsoft Jet 3.5 Available on MSL Additional query words:
Keywords : kbVBp400 vbwin |
Last Reviewed: April 15, 1999 © 2000 Microsoft Corporation. All rights reserved. Terms of Use. |