摘要
The constraints and the operations play an important role in database generalization.They guide and govern database generalization.The constraints are translation of the required conditions that should take into account not only the objects and relationships among objects but also spatial data schema (classification and aggregation hierarchy) associated with the final existing database.The operations perform the actions of generalization in support of data reduction in the database.The constraints in database generalization are still lack of research.There is still the lack of frameworks to express the constraints and the operations on the basis of object_oriented data structure in database generalization.This paper focuses on the frameworks for generalization operations and constraints on the basis of object_oriented data structure in database generalization.The constraints as the attributes of the object and the operations as the methods of the object can be encapsulated in classes.They have the inheritance and polymorphism property.So the framework of the constraints and the operations which are based on object_oriented data structure can be easily understood and implemented.The constraint and the operations based on object_oriented database are proposed based on object_oriented database.The frameworks for generalization operations,constraints and relations among objects based on object_oriented data structure in database generalization are designed.The categorical database generalization is concentrated on in this paper.
The constraints and the operations play an important role in database generalization. They guide and govern database generalization. The constraints are translation of the required conditions that should take into account not only the objects and relationships among objects but also spatial data schema (classification and aggregation hierarchy) associated with the final existing database. The operations perform the actions of generalization in support of data reduction in the database. The constraints in database generalization are still lack of research. There is still the lack of frameworks to express the constraints and the operation on the basis of object-oriented data structure in database generalization. This paper focuses on the frameworks for generalization operations and constraints on the basis of object-oriented data structure in database generalization. The constraints as the attributes of the object and the operations as the methods of the object can be encapsulated in classes. They have the inheritance and polymorphism property. So the framework of the constraints and the operations which are based on object-oriented data structure can be easily understood and implemented. The constraint and the operations based on object-oriented database are proposed based on object-oriented database. The frameworks for generalization operations, constraints and relations among objects based on object-oriented data structure in database generalization are designed. The categorical database generalization is concentrated on in this paper.
基金
ProjectsupportedbytheInternationalInstituteforAerospaceSurveyandEarthScience
MinistryofEducationandtheStateBureauofSurveyingandMapping.
