Visual C++ Extensions for ADO

The preferred method of programming ADO with Visual C++ is using the #import directive, as discussed in Microsoft Visual C++ ADO Programming. However, earlier versions of ADO shipped with an alternate method of programming using Visual C++: the Visual C++ Extensions. This section documents this feature for those who must maintain Visual C++ Extensions code, but new ADO code should be written using #import.

One of the most tedious jobs Visual C++ programmers face when retrieving data with ADO is converting data returned as a VARIANT data type into a C++ data type, and then storing the converted data in a class or structure. In addition to being cumbersome, retrieving C++ data through a VARIANT data type diminishes performance.

ADO provides an interface that supports retrieving data into native C/C++ data types without going through a VARIANT, and also provides preprocessor macros that simplify using the interface. The result is a flexible tool that is easier to use and has great performance.

A common C/C++ client scenario is to bind a record in a Recordset to a C/C++ struct or class containing native C/C++ types. When going through VARIANTs, this involves writing conversion code from VARIANT to C/C++ native types. The Visual C++ Extensions for ADO are targeted at making this scenario much easier for the Visual C++ programmer.

See the following topics to learn more about the Visual C++ Extensions for ADO.

• Using Visual C++ Extensions for ADO

• Visual C++ Extensions Header

• ADO with Visual C++ Extensions Example

See Also

ADO for Visual C++ Syntax Index for COM Visual C++ Extensions Example Using Visual C++ Extensions Visual C++ Extensions Header