This chapter and the following chapter focus on ADO, which stands for ActiveX
Data Objects. ADO is a general object model that is Microsoft's latest programming
interface for access to data provided by OLE DB.
OLE DB is, in turn, an open standard for providing data access. Various OLE DB data
providers (or just providers) now exist. OLE DB providers include those for Microsoft Jet
databases, SQL Server, and ODBC.
A programmer using ADO can connect to a data source through one of the existing
OLE DB providers. The programmer can then manipulate this data by using the ADO object model.
OLE DB in turn is an implementation of Microsoft's Universal Data
Access model (UDA). The UDA is a general COM-based standard for access
to any type of data source, no matter how exotic.
Besides typical data sources such as databases and spreadsheets, UDA aims
to include anything that can be considered as a "data source" in the broad sense
of the term. Examples of some of the more unexpected types of data sources might include file directory
structures, text files, or COM ports.
Veteran (and even less-than-veteran) VB programmers will recall with varying degrees
of fondness and other emotions such data access models as Jet, DAO (Data Access Objects), and
RDO (Remote Data Objects). Although these data-access models are still available in VB6, Microsoft
wants programmers to do all new data development with the ADO model.
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