Microsoft Data Access Components (MDAC)

The Microsoft® Data Access Components (MDAC) SDK documents the key technologies that are part of Microsoft's strategy for providing access to information across the enterprise.

Microsoft Data Access Components include ActiveX® Data Objects (ADO), OLE DB, and Open Database Connectivity (ODBC). Data-driven client/server applications deployed over the Web or a LAN can use these components to easily integrate information from a variety of sources, both relational (SQL) and non-relational.

If you have questions or need detailed information about properly redistributing MDAC, see Redistributing MDAC for a description of the distribution requirements for MDAC.

ActiveX Data Objects (ADO)

Microsoft ActiveX Data Objects (ADO) provides consistent, high-performance access to data and supports a variety of development needs, including the creation of front-end database clients and middle-tier business objects that use applications, tools, languages, or Internet browsers. The primary benefits of ADO are ease of use, high speed, low memory overhead, and a small disk footprint.

ADO provides an easy-to-use interface to OLE DB, which provides the underlying access to data. It uses a familiar metaphor — the COM Automation interface — available from all leading Rapid Application Development (RAD) tools, database tools, and languages.


Microsoft OLE DB is a set of interfaces that expose data from a variety of relational and nonrelational sources by using the Component Object Model (COM). OLE DB interfaces provide applications with uniform access to data stored in diverse information sources. These interfaces support the amount of DBMS functionality appropriate to the data store, enabling the data store to share its data.

OLE DB comprises a programmatic model consisting of data providers, which contain and expose data; data consumers, which use data; and service components, which process and transport data (such as query processors and cursor engines). In addition, OLE DB includes a bridge to ODBC to enable continued support for the broad range of ODBC relational database drivers.

Open Database Connectivity (ODBC)

The Microsoft Open Database Connectivity (ODBC) interface makes it possible for applications to access data from a variety of DBMSs. ODBC permits maximum interoperability — an application can access data in diverse DBMSs through a single interface. Furthermore, that application will be independent of any DBMS from which it accesses data. Users of the application can add software components called drivers, which create an interface between an application and a specific DBMS.

Components of the MDAC SDK

Microsoft ActiveX Data Objects (ADO)

This section contains Programmer's References for ADO, ADOX, ADO MD, and RDS, as well as samples documentation.

Microsoft OLE DB

This section documents the OLE DB and OLE DB for OLAP interfaces, including a Programmer's Reference, documentation for various OLE DB providers, and samples.

Microsoft Open Database Connectivity (ODBC)

This section documents the ODBC interface, including a Programmer's Reference, documentation for various ODBC drivers, and samples.