Understanding how to use Microsoft Access files in ArcGIS

You can use tables from a Microsoft Access database in ArcMap through an OLE DB connection. OLE DB is a standard for sharing data between applications, enabling you to view the Access database in ArcMap. To maintain data integrity, you should only modify an Access database in Access.

Similarly, you should only edit a personal geodatabase in ArcGIS. Although a personal geodatabase is stored as an Access .mdb, you should not open or modify the tables in a personal geodatabase inside Microsoft Access. This can corrupt the geodatabase and cause data loss.

The limitation of Microsoft Access as an application to edit personal geodatabases is that Access was not designed to use or understand the ESRI functionality behind the personal geodatabase format. For example:

• The Access database format does not support geographic features.
• Personal geodatabases contain multiple underlying tables that provide information for a single feature class. When editing a feature class in ArcGIS, ArcGIS keeps track of changes in all the underlying tables. Editing the geodatabase in Access may cause those tables to become out of sync and corrupt the geodatabase.

Microsoft Office 2007 introduced a new Microsoft Access database format, accdb, which is the new default format in Access 2007 when saving or creating a database. Without using OLE DB, ArcGIS cannot directly read or write to the new Microsoft Access format; this includes accessing accdb files directly through the Add Data dialog box.