ActiveX Data Objects
By now you should be sufficiently attuned to Microsoft terminology to realize that terms using Active are (a) invented by their marketing department and devoid of precise technical meanings and (b) probably something to do with COM. ActiveX Data Objects (ADO) is not a new technology, but simply an easy-to-use COM object hierarchy on top of OLEDB. It is bundled with Visual Basic and Visual C++ 5.0 and higher; look in the MakePy window for Microsoft ActiveX Data Objects Library 2.0. It looks superficially similar to DAO and RDO but offers vastly greater capabilities under the hood and is thoroughly geared to the needs of client/server systems. Microsoft has stated that they will put no effort into further enhancements of RDO, DAO, and ODBC (although they are committed to supporting ODBC for the long haul), so ADO sounds like the COM interface of the future. Here are some of the enhancements offered:
A programmer can trap events before or after commands are executed.
A command object wraps stored procedures and simplifies setting parameters.
ADO exposes objects that wrap up the data definition language of a data store, meaning you can write code to create and modify tables and indexes, which works against a variety of underlying databases, even nonrelational ones.
ADO supports hierarchical recordsets, which consist of prejoined master and detail recordsets.
Disconnected recordsets and batch updates are perhaps the most exciting features. An application for a salesman ...
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