An important dimension in the database technology evolution is the development of advanced/sophisticated database models. In particular, the viewpoint concept receives a widespread attention. Its integration to a data...
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ISBN:
(纸本)9728865198
An important dimension in the database technology evolution is the development of advanced/sophisticated database models. In particular, the viewpoint concept receives a widespread attention. Its integration to a data model gives a flexibility for the conventional object-oriented data model and allows one to improve the modeling power of objects. On the other hand, the viewpoint concept can be used as a means to master the complexity of the current systems permitting a distributed manner to develop them. In this paper we propose a data model MVDB (Multi-Viewpoint DataBase model) that extends the object database model with the viewpoint mechanism. The viewpoint notion is used as an approach for a distributed development of a database schema, as a means for object multiple description and as a mechanism for dealing with the integrity constraint problems commonly met in distributed environment.
While the dominant approach to persistent storage in practice is to use a relational DBMS, there are some specialist applications that rely on object stores. The performance of these applications depends on the effici...
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While the dominant approach to persistent storage in practice is to use a relational DBMS, there are some specialist applications that rely on object stores. The performance of these applications depends on the efficiency of the object store's concurrency control mechanism. Today's predominant concurrency control mechanism is strict two-phase object locking. In the 1980s, an interesting alternative was developed: commutativity-based semantic locking. In theory, it can outperform traditional locking schemes in certain scenarios with appropriate commutativity potential. In this paper, we study the real-world performance of different locking strategies in a particular industrial application from the telecommunications sector. We compare object-based locking and commutativity-based semantic locking. We found that, in this application, semantic locking performs equally to, but no better than, object locking in reasonable mixes of real-world transactions, and that it only outperforms in a deliberately contrived mix.
Lack of parametric polymorphism has been a major obstacle for making Java a viable database programming language. Regrettably, a recently accepted solution for genericity in Java 5.0 has far-reaching negative implicat...
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Lack of parametric polymorphism has been a major obstacle for making Java a viable database programming language. Regrettably, a recently accepted solution for genericity in Java 5.0 has far-reaching negative implications for persistent and database systems because of static and dynamic type violations. Severe implications occur in typical database transactions when processing a variety of database collections. Well-known approaches to persistence in Java, including Java's own persistence mechanism, do not perform correctly due to incorrect dynamic type information that gets promoted to persistence along with objects. Dynamic checking of types of objects fetched from the persistent store may now lead to unexpected type violations. Further problems occur in reflective transactions as Java Core Reflection now allows dynamic type violations without detecting them or throwing standard exceptions. All of this shows that extending Java with parametric polymorphism has not made Java a more viable database programming language. Both legacy systems, such as those based on the Java binding of the ODMG or JDO, and future Java-related persistent and database technologies will be affected. The source of these problems is in an implementation idiom called type erasure. This paper provides formal proofs of the above implications of type erasure along with specific samples of code in Java 5.0 illustrating these violations. The limitations of the virtual platform and extensions required for persistent systems to solve this problem are also elaborated.
An overview of the current status in the area of formal technique of object database design is described in the article. It is discussed here, why relational normalization is not able to be easy used in object databas...
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ISBN:
(纸本)9781402087400
An overview of the current status in the area of formal technique of object database design is described in the article. It is discussed here, why relational normalization is not able to be easy used in objectdatabases. The article introduces various proposals of object normal forms and it brings own authors' evaluation in this area.
This paper handles the conversion from an existing XML-Schema into object-oriented database. The major motivation for this work is to store XML-Schema into objectoriented database. There are more common features betw...
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ISBN:
(纸本)9781424426591
This paper handles the conversion from an existing XML-Schema into object-oriented database. The major motivation for this work is to store XML-Schema into objectoriented database. There are more common features between the object-oriented model and XML, and thus it is more attractive to map from XML into object-oriented database;such mapping preserves database specifics. To achieve the mapping, what we call the object graph is derived based on characteristics of the XML-Schema;it simply summarizes and includes all complex and simple elements and the links, which are the basics of the XML-Schema. Then, the links are simulated in terms of nesting to get a simulated object graph. This way, everything in a simulated object graph is directly representable in object-oriented database. Finally, we handle the mapping of the actual data from XML document(s) into the corresponding object-oriented database.
Persistent object Stores provide the core of the physical architecture of database management systems (DBMSs). Persistence, concurrent access, transaction support, and direct, navigational and associative object acces...
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Nowadays the application of temporal databases in modern information systems becomes more and more popular. Time-varying information with valid time, transaction time or both are required by typical applications such ...
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ISBN:
(纸本)9780889867307
Nowadays the application of temporal databases in modern information systems becomes more and more popular. Time-varying information with valid time, transaction time or both are required by typical applications such as human resource management, medical information systems, agriculture and farm management. Also, the object-oriented paradigm is now the standard paradigm for software development. objectdatabases are widely available commercially. However, the concept of temporal database is still not included as a standard feature and the users have to implement them at the application level. This paper presents temporal object database implementation techniques. The techniques can accommodate attribute timestamping both at the object class and the association between object classes. A software tool based on the proposed techniques is developed.
In this work, we introduce a score fusion scheme to improve the 3D object retrieval performance. The state of the art in 3D object retrieval shows that no single descriptor is capable of providing fine grain discrimin...
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Knowledge discovery in database have been attracting a significant amount of research, industry attention in recent years. Process planning knowledge (PPK) is one of the most important knowledge in mechanical manufact...
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