Access 2003 VBA Programmer's Reference

6.1. Direct Access Objects

DAO is the programmatic interface between VBA and Jet databases, ODBC (Open Database Connectivity) data stores, and installable ISAM (Indexed Sequential Access Method) data sources, such as Excel, Paradox, dBase, and Lotus 1-2-3.

As is described in greater detail a little later in this section, DAO supports two different data access environments, or workspaces: Microsoft Jet and ODBCDirect. You use Microsoft Jet workspaces when you need to take advantage of Jet's unique features, such as the ability to link data from different database formats.

DAO was first released as a part of Visual Basic 2.0, and was known internally at Microsoft as VT Objects, which provided a limited set of options for interacting with ODBC data sources. In November 1992, DAO 1.0 was released as part of Access 1.0. It provided Access developers with a limited set of database objects for manipulating the Microsoft Jet data engine. Improvements in DAO version 2.0 (released with Access 2.0) meant that programmers were afforded almost complete control over creating and modifying database objects, as well as manipulating data using a variety of recordset types. DAO 2.5 was created for both 16- and 32-bit platforms, and was designed for use with ODBC Desktop Database Drivers 2.0.

In 1995, Microsoft simultaneously released DAO 3.0 in both Access 95 and Visual Basic 4.0, offering full 32-bit type libraries, plus several extra properties and methods to complete the object model. In addition, ...