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The DAIS::DataAccess::Session object implements the data access service on a per client basis. A data access session object
has a number of services provided by one singleton home object each. Each home object provides methods for manipulation of
the data of the specific type they provide. Rather than exposing data as objects with interfaces it is exposed as structs
or sequences of structs. The reason is that a large number of data items will become a performance bottleneck if instantiated
as objects over an interface. The DAIS::Group::IHome object is the only object to expose its data as objects; that is, the
DAIS::Group::Manager. Each DAIS::Group::Manager is expected to connect to one callback object implemented by the client.
Each client may instantiate one or more Sessions. The Session objects have one Type and Property Home object each. The client
shall expect that all Type and Property Home objects expose the same types and properties.
The session object corresponds to an OPCServer object.
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Figure 4-5 DAIS data access session IDL in UML