Databases Reference
In-Depth Information
between software components. Thus, simply put, OLE DB is a set of functions or
services.
Figure 17-2 gives an overview of ADO and OLE DB from a VB programmer's
perspective.
Figure 17-2. OLE DB and ADO
17.3.1 Data Stores
The purpose of OLE DB is to provide applications with universal data access—that is,
with a common method for accessing data in essentially any format, including traditional
database formats, text formats, spreadsheet formats, email formats, file system formats,
web-based formats, and more. OLE DB uses the term
data store
to refer to any data that
can be accessed through the OLE DB services. The term
data source
seems to be a
synonym for data store, although this term is used in different ways in other related
contexts (such as the VB6 DataBinding object model). Indeed, the term “data source” is
one of the most abused in Microsoft's arsenal.
17.3.2 Data Providers
In order to create access to a particular type of data, a developer must write an OLE DB
data provider
for that type of data store. This is usually done in a C-type development
environment such as Visual C++, but it can be done in VB as well.
The purpose of an OLE DB data provider is to expose the data in data stores of a
particular type in
tabular
format, with rows (records) and columns (fields). In other
