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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