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Show 18 f'aciliti e:-; to merge versions and to freeze configurations when no furthe r ve rsioning is des ired . Obj ectS tore bas its own query language for navigational and associative retri e val uf' objects . Fot e~[icien t retrieval , it p erform s query opt imi zation and allows indices tu lw httilt on collections uf objects. 2.5.9 Ontos Onto:-; , [5, 3] [onnerly \!Base, was developed by Ontologie, Inc. It provides persistence to classes a nd obj ects crea.ted in C++. ft has been implemented ustng C++. Objects are gtveu UIDs and there are two ways of referring to these objects, 'l'r<t n:opareut (TRef) and direct r e f'er(:~ nc c s. Objects pointed to by TRefs are auLotll a tically activated (tbe object is fault ed in) upon reference, whereas for direct re ference , an explicit activation call l1as to be made to load the object into the Ill emory. Ont us pru vicl cs t hn·c l,ViH'S uf' obj ect !, ttffe t·in g: I. No-buffering - The modifi ed objects arc immedi a tely trausfcrred to th e :-i ( 'I' \It' !' ·) Default-buffering- Objects are sent in small groups, e .g ., af'tcr ten requests l' (LCh . :3. Buffer-until-commit - Objects are buffer ed until the t ransaction ts comrnittcd . Ontos p rovid es three types of locks: Tn ui, wriLcinten.t (for objects that are likely iu lw modified ) a ncl no/ock (for reading objects without locking the object). 'T'Ltese loc ks can be ob t a in ed urtder two modes: |
