Introduction to the Access 2007 file format
Microsoft Office Access 2007 creates files in a new file format that cannot be opened with earlier versions of Access. This article describes the new features of the Office Access 2007 file format, reviews some issues that arise when you convert to earlier file formats, and summarizes how some related file types have changed from earlier versions.
In this article
New features of the Access 2007 file format
In Office Access 2007, the Microsoft Jet database engine has been customized for 2007 Microsoft Office system programs. This Office-specific version of Jet, called the Access Database Engine, enables integration with Windows SharePoint Services 3.0 and Microsoft Office Outlook 2007 and creation of multivalued lookup fields and makes other improvements.
Multivalued lookup fields Most database programs, including earlier versions of Access, allow you to store only a single value in each field. In Office Access 2007, however, you can create a lookup field that allows you to store more than one value in each field. In effect, Access creates a many-to-many relationship within the field and hides the details of the implementation by using system tables.
For example, suppose you have a Task table that contains a lookup field that you use to assign tasks to employees. What if you need to assign a task to several employees? In earlier versions of Access, you must set up a new cross-reference table to store each combination of task and employee and then revise your forms and reports to use the new data structure. In Office Access 2007, a multivalued lookup field makes this process much easier. Items are no longer grouped in a drop-down list. Now each item in the list has a check box next to it, so that you can select as many items as you want. Multiple selections are displayed in the field, separated by commas.
Find links to more information about multivalued lookup fields in the See Also section.
Attachment data type Use the new Attachment data type to easily store all types of documents and binary files in your database without unnecessary database bloat. To maximize space usage, attachments are automatically compressed when it is appropriate. For example, you can attach a Microsoft Office Word 2007 document to a record or save a series of digital pictures. You can even have multiple attachments to a single record.
Find links to more information about attaching files to records in the See Also section.
Integration with Windows SharePoint Services 3.0 and Office Outlook 2007 In earlier versions, Access files are blocked from Windows SharePoint Services and Outlook because unsafe code could be included in an Access database. Office Access 2007 implements a new format that allows code to be either verified as safe or disabled. This feature makes it possible to integrate Access databases much more fully with Windows SharePoint Services and Office Outlook 2007. It also allows antivirus programs to inspect Access database files much more easily.
Offline data You can take your SharePoint lists offline with one click by using Office Access 2007. You can work on your data in Access and then synchronize your changes, or reconnect with the SharePoint site at a later time.
History tracking for Memo fields Memo fields are useful for storing large amounts of information. In Office Access 2007, you can set a property (AppendOnly) that forces Access to retain a history of all changes to a Memo field. You can then view a history of those changes. This feature also supports the versioning feature in Windows SharePoint Services 3.0 so that you can use Access to track changes in a "multiple lines of text" field that is stored in a SharePoint list. The field must have the Append Changes to Existing Text option set to Yes.
Conversion to earlier file formats
The new features described in the previous section are not available in versions of Access earlier than Office Access 2007. If you create an Office Access 2007 database that uses of any of these features and you attempt to save it as an earlier version database (for example, as an Access 2002-2003 or an Access 2000 database), Access displays the following message.
You cannot convert the database to an earlier version (.mdb) format unless you revise the database so that it no longer uses these features.
This section summarizes the file types that are used by the Office Access 2007 file format.
.accdb This is the standard file name extension for databases in the Office Access 2007 file format. This format takes the place of the .mdb file name extension that is used in earlier versions of Access.
.accde This is the file name extension for Office Access 2007 files that are compiled into an "execute only" file. This format takes the place of the .mde file name extension that is used in earlier versions of Access.
An .accde file is a "locked-down" version of the original .accdb file. If the .accdb file contains any Visual Basic for Applications (VBA) code, only the compiled code is included in the .accde file. As a result, the VBA code cannot be viewed or modified by the user. Also, users working with .accde files cannot make design changes to forms or reports. You create .accde files from .accdb files by doing the following:
In Office Access 2007, open the database that you want to save as an .accde file.
On the Database Tools tab, in the Database Tools group, click Make ACCDE.
In the Save As dialog box, browse to the folder in which you want to save the file, type a name for the file in the File name box, and then click Save.
.accdt This is the file name extension for Access Database Templates.
.accdr The .accdr file is a new file name extension that enables you to open a database in run-time mode. By changing a database's file name extension from .accdb to .accdr, you can create a "locked-down" version of your Office Access 2007 database. You can change the file name extension back to .accdb to restore full functionality to your database.
.mdw The workgroup information files store information for secured databases. No changes were made to the .mdw file format for Office Access 2007. The Office Access 2007 Workgroup Manager creates .mdw files that are identical to those that are created in Access 2000 through Access 2003. The .mdw files that are created in those earlier versions can be used by databases in Office Access 2007.
Note You can use Office Access 2007 to open an earlier-version database that has been secured by using user-level security. However, user-level security does not exist in Office Access 2007 databases. There is no command on the Ribbon (part of the Microsoft Office Fluent user interface) to start the Workgroup Manager, but you can still start the Workgroup Manager in Office Access 2007 by using the DoCmd.RunCommandacCmdWorkgroupAdministrator command in VBA code, or by creating an Access macro that contains the RunCommand action with a Command argument of WorkgroupAdministrator.
.laccdb When you open an Office Access 2007 database, file locking is controlled by a locking file with the file name extension .laccdb. The .laccdb file corresponds to the .ldb locking file that is created when you open an earlier version Access (.mdb) file. The type of locking file that is created depends on the file type of the database that is being opened, not which version of Access you are using. For example, if you open the file Db1.mdb, Access creates and opens a file named Db1.ldb. By contrast, if you open the file Db1.accdb, Access creates and opens a file named Db1.laccdb. Locking files are deleted automatically when all users close the database.
If separate locking files are maintained for both Office Access 2007 files and files that are created in earlier versions of Access, it is possible to have databases named Db1.mdb and Db1.accdb open in Office Access 2007 at the same time without creating any locking file conflicts. This is because two different locking files (.ldb and .laccdb) are created. Also, it is possible for one user to open an .mdb file in Office Access 2007 while another user opens the same .mdb in an earlier version of Access. In this case, both sessions use the same .ldb locking file.
You can link a table from an earlier Access file format to a database in a later version of Access, but you cannot link a table from a later version of Access to a database in an earlier version of Access. For example, you can link from an .accdb database to tables in another .accdb database, or to tables in an .mdb database. However, you cannot link from an .mdb database to tables in an .accdb database.
Replication is not supported in the Office Access 2007 file format. You can use Office Access 2007 to replicate a database that was created in an earlier file format, but not a database that was created in the Office Access 2007 format.