 |
 |
 |
 |
 |
 |
 |
| OLE DB Overview | ||
OLE DB is a set of COM interfaces which implements the uniform access to data using the Universal Data Access mechanism. The OLE DB architecture uses the model of consumers and providers. A consumer makes the requests and the provider responds to these requests by placing data in a tabular format. A consumer is any system or application code (not necessarily an OLE DB component) that accesses data through OLE DB interfaces. The interfaces are implemented by the provider and thus, a provider is a component that implements OLE DB interfaces and expose it to other objects. The OLE DB Object Model comprises of a number objects or components, which in sync works to achieve the basic functionalities of OLE DB mechanism. The OLE DB objects can be listed as 1. Data Source It creates and manages the connection and contains permissions and authentications information 2. Sessions A session manages a particular instance of interaction with the data source to query and retrieve data. 3. Commands A command is a container for a text command, which is passed from a consumer to a data source object for execution by the provider's underlying data store 4. Rowsets Rowset is used to expose data in a tabular format. 5. Accessors An accessor is used to describe how the data will be stored in the consumer, like the binding between the rowset fields and the data members in the consumer. 6. Transactions Transaction objects are used to bundle a set of indivisible work unit. 7. Enumerators It search and stores the list of available data sources and other enumerators. 8. Errors Error objects contain additional information on error. 9. Notifications Notification objects enable cooperating consumers sharing the rowset to be informed about actions on the rowset performed by their peers. For implementation of OLE DB supported applications, we can use the ATL OLE DB Templates, MFC OLE DB Classes or the OLE DB SDK interfaces itself. The OLE DB templates are C++ templates, providing classes that implement many commonly used OLE DB interfaces and the template library is categorized into consumer templates and provider templates. |
||
 |
||
Data Bound Controls (ADO and RDO)
Universal Data Access
