Access File Formats: ACCDB vs MDB

The release of Access 2007 brings a new file format. The MDB database files we’ve known for over a decade are now slated to become historical relics. While Access 2007 continues to support MDB databases for backwards compatibility purposes, Microsoft has now introduced the new ACCDB file format as the future standard. Wondering if you should begin using the ACCDB format? Let’s consider a few frequently asked questions.

What benefits come with the new format?

The new format supports functionality not available in earlier versions of Access. Specifically, by using the ACCDB format, you will be able to:

• Include attachments in your database. The ACCDB format allows you to store file attachments and other binary large objects (or BLOBs) in database fields. This is a feature common to enterprise databases such as Oracle and SQL Server that’s been missing from Microsoft Access.
• Use multivalued fields. While database purists may scoff at the idea of multivalued fields because they defy the principles of normalization, they’ll make life easier for developers of simple databases. Multivalued fields offer you the opportunity to allow users to select one or more options for a field value by using checkboxes. For example, you could create a Shirt Sizes field with the values S, M, L, and XL. Users could then select all values that apply from the multivalued field.
• Safe integration with SharePoint and Outlook. SharePoint and Outlook both block MDB databases due to security concerns. Improvements in the database security model allow for the security validation of database files and both SharePoint and Outlook trust this validation.
• Encryption improvements. Users of ACCDB files may leverage the Windows Cryptographic API for database encryption. This capability is especially important in this day and age of identity theft where an encrypted database can mean the difference between an embarrassing and costly security incident and a non-event. This site offers a detailed look at Microsoft Access encryption.

Should I use the ACCDB format for new databases?

If you want to leverage any of the advantages listed above, you may wish to consider creating new databases in the ACCDB format. However, you should keep in mind that users of older versions of Access will not be able to work with your new databases. If you collaborate with others, you shouldn’t make the switch until all users are running Access 2007.

There are also two limitations that you should consider before making the switch to ACCDB. ACCDB databases do not support user level security or replication. If you need either of these features, you should stick with MDB format for the time being.

Should I convert existing databases to the ACCDB format?

If you have existing MDB databases created with earlier versions of Access, you may wish to consider converting them to ACCDB format. In fact, depending upon the version of Access used to create the file, you may be required to convert. Here are the specifics:

• Access 2002-2003 databases may be converted if you desire the enhanced functionality of ACCDB databases.
• Access 2000 databases may be converted if you desire the enhanced functionality of ACCDB databases.
• Access 97 databases must be converted or you will not be able to make design changes to your database.
• Access 95 databases must be converted or you will not be able to make design changes to your database.

If you'd like to convert an existing database to Access 2007 format, read the article How to Convert a Database to Access 2007 Format.