The top of the diagram is the OSession.
Next is OServer, followed by ODatabase
The diagram indicates that the following are created from ODatabase:
OSQLStmt
ODynaset
OParameters
OParameterArray
OMetaData
OAQ
The diagram also indicates the following:
OField belongs to ODynaset object.
OParameter belongs to OParameters object.
OMDAttribute belongs to OMetaData object.
OAQMsg belongs to OAQ object.