file extension MDN

Microsoft Access (current full name Microsoft Office Access) is a relational database management system from Microsoft, packaged with Microsoft Office Professional which combines the relational Microsoft Jet Database Engine with a graphical user interface.

Microsoft Access can use data stored in Access/Jet, Microsoft SQL Server, Oracle, or any ODBC-compliant data container. Skilled software developers and data architects use it to develop powerful, complex application software. Relatively unskilled programmers and non-programmer "power users" can use it to build simple applications without having to deal with features they don't understand. It supports substantial object-oriented (OO) techniques but falls short of being a fully OO development tool.

Office Access 2007 introduces a few new file extensions:

• ACCDB The file extension for the new Office Access 2007 file format. This takes the place of the MDB file extension.
• ACCDE The file extension for Office Access 2007 files that are in "execute only" mode. ACCDE files have all Visual Basic for Applications (VBA) (Visual Basic for Applications (VBA): A macro-language version of Microsoft Visual Basic that is used to program Microsoft Windows-based applications and is included with several Microsoft programs.) source code removed. A user of an ACCDE file can only execute VBA code, not modify it. ACCDE takes the place of the MDE file extension.
• ACCDT The file extension for Access Database Templates.
• ACCDR ACCDR is a new file extension that enables you to open a database in runtime mode. By simply changing a database's file extension from .accdb to .accdr, you can create a "locked-down" version of your Office Access 2007 database. You can change the file extension back to .accdb to restore full functionality.

New features of the Office Access 2007 file format

Multivalued lookup fields Most database programs, including prior versions of Access, only allow you to store a single value in each field. In Office Access 2007, however, you can now create a lookup field that allows you to store more than one value in each field. In effect, it creates a many-to-many relationship within the field, and hides the details of the implementation using system tables.

For example, suppose you have a Task table with a lookup field that you used to assign the task to an employee. What if you have a task that you need to assign to several employees? In earlier versions of Access, you would need to set up a new cross-reference table to store each combination of task and employee, then revise your forms and reports to use the new data structure. In Office Access 2007, this is made much easier by implementing a multivalued lookup field. Instead of being able to select only one item from a drop-down list, now each item in the list has a check box next to it so that you can select as many as you like. The 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 The new Attachment data type lets you easily store all types of documents and binary files in your database without unnecessary database bloat. Attachments are automatically compressed when appropriate to maximize space usage. 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 attached to a single record.

For more information about attaching files to records, see the links in the See Also section.

Integration with Microsoft Windows SharePoint Services 3.0 and Microsoft Office Outlook 2007 In the past, Access files have been blocked from Windows SharePoint Services 3.0 and Office Outlook 2007 due to the fact that unsafe code could be included within an Access database. Office Access 2007 implements a new format that allows code to be either verified as safe or disabled. This makes it possible to integrate Access databases much more fully with Windows SharePoint Services 3.0 and Office Outlook 2007, and it also allows anti-virus programs to inspect Access database files much more easily.

Work with your SharePoint data offline You can take your SharePoint lists offline with one click using Office Access 2007. Work on your data in Access and then synchronize your changes, or reconnect with the SharePoint site at a later time.

Memo field history tracking Memo fields are useful for storing large amounts of information. Starting with 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 stored in a SharePoint list (provided that the field has the Append Changes to Existing Text option set to Yes).