Derived Objects and Classes in DOOD Systems
نویسندگان
چکیده
The closure property is essential to enhance the power of database languages. In the deductive object-oriented database (DOOD) context, this property implies that the rule-derived objects as well as the rule-derived classes (i.e. the classes populated by the derived objects) be established with full OO (objectoriented) features. This paper provides the methods of specifying the OO features of derived classes (i.e. the populations of derived classes and the class hierarchies including derived classes) by their population rules. The work is based on a deductive language, called ERCLog, for an object and relationship data model. The principles can be applied to other DOOD languages which distinguish the notions of schema and instance of databases.
منابع مشابه
Super-Key Classes for Updating Materialized Derived Classes in Object Bases
We describe data structures that allow e cient updates of materialized classes derived from relationship of classes in object bases. Materialization of derived classes reduces costs of retrievals and increases costs of updates. Costs of updates increase remarkably when several paths of objects derive the same object. If object bases satisfy the superkey condition proposed in this paper, consist...
متن کاملForty Years of X-Ray Binaries
In 2012 it was forty years ago that the discovery of the first X-ray binary Centaurus X-3 became known. That same year it was discovered that apart from the High-Mass X-ray Binaries (HMXBs) there are also Low-Mass X-ray Binaries (LMXBs), and that Cygnus X-1 is most probably a black hole. By 1975 also the new class of Be/X-ray binaries was discovered. After this it took 28 years before ESAs INTE...
متن کاملObjects Identification in Object-Oriented Software Development - A Taxonomy and Survey on Techniques
Analysis and design of object oriented is onemodern paradigms for developing a system. In this paradigm, there are several objects and each object plays some specific roles. Identifying objects (and classes) is one of the most important steps in the object-oriented paradigm. This paper makes a literature review over techniques to identify objects and then presents six taxonomies for them. The f...
متن کاملSymplectic and symmetric methods for the numerical solution of some mathematical models of celestial objects
In the last years, the theory of numerical methods for system of non-stiff and stiff ordinary differential equations has reached a certain maturity. So, there are many excellent codes which are based on Runge–Kutta methods, linear multistep methods, Obreshkov methods, hybrid methods or general linear methods. Although these methods have good accuracy and desirable stability properties such as A...
متن کاملModeling and Evaluation of Stochastic Discrete-Event Systems with RayLang Formalism
In recent years, formal methods have been used as an important tool for performance evaluation and verification of a wide range of systems. In the view points of engineers and practitioners, however, there are still some major difficulties in using formal methods. In this paper, we introduce a new formal modeling language to fill the gaps between object-oriented programming languages (OOPLs) us...
متن کامل