This is a hierarchy diagram.
The top of the diagram is the OraSession.
Next is OraServer, followed by OraDatabase
The diagram indicates that the following are created from OraDatabase:
The diagram also indicates the following:
OraField belongs to the OraDynaset object.
OraParameter belongs to the OraParameters object.
OraMDAttribute belongs to the OraMetaData object.
OraAQMsg belongs to the OraAQ object.