7.7.9.Creating and Using Accessors
Consumers describe the memory structure for their buffers through a process called binding. An accessor is a group of bindings. The OpenLink provider does not currently support reference accessors, which allow the consumer direct access to the rowset's data cache.
Accessors are implemented through IAccessor. Accessors are created with IAccessor::CreateAccessor and released with IAccessor::ReleaseAccessor. IAccessor::GetBindings can be used to determine the bindings in an existing accessor. IAccessor::AddRefAccessor enables the consumer to add a reference count to an existing accessor.
Accessors may not always be validated immediately at the time of creation. Instead, they may be validated at the time the first row is fetched. Errors will be returned at the first attempt to use such an accessor.
Creating an Accessor
CreateAccessor associates a set of bindings with an accessor handle that is used to send data to or fetch data from the rowset's data cache. The OpenLink provider supports only the DBACCESSOR_ROWDATA accessor flag, which specifies that the accessor is to be used for rowset data.
Returning Accessor Bindings
GetBindings returns the bindings in an existing accessor.
Adding a Reference Count to an Existing Accessor
AddRefAccessor adds a reference count to an existing accessor.
Releasing an Accessor
ReleaseAccessor decrements the reference count on an accessor; when the reference count reaches zero, the accessor is released.