Aim To develop a heterogeneous database united system(HDBUS)that combines the local database of Oracle, Sybase and SQL server distributed on different server into a global database,and supports the global transaction...Aim To develop a heterogeneous database united system(HDBUS)that combines the local database of Oracle, Sybase and SQL server distributed on different server into a global database,and supports the global transaction management and parallel query over the Intranet Methods In the designing and implementation of HDBUS two important concepts heterogeneous tables join. Results and Conclu- tion The first concept can be used to process the parallel query of multiple database server, the second one is the key technology of heterogeneous is the key technology of heterogeneous distribute database.展开更多
This paper defines a new kind of rule, probability functional dependency rule. The functional dependency degree can be depicted by this kind of rule. Five algorithms, from the simple to the complex, are presefited to ...This paper defines a new kind of rule, probability functional dependency rule. The functional dependency degree can be depicted by this kind of rule. Five algorithms, from the simple to the complex, are presefited to mine this kind of rule in different condition. The related theorems are proved to ensure the high efficiency and the correctness of the above algorithms.展开更多
<正> To process the data with strong historical features, such as data in earthquake research,weather forecast, medical records and census, a new mathematical model of historical datasystem is proposed. This mod...<正> To process the data with strong historical features, such as data in earthquake research,weather forecast, medical records and census, a new mathematical model of historical datasystem is proposed. This model can be characterized as ' relational database with timemark + histotical rule base = historical database', and it is easy to implement. The formaldescription of historical database and a special class of historical rules-premonitory de-pendency (abbreviated as PD)-are discussed, the poperties and inference axioms of PDare investigated. The soundness and completeness of the axioms are proved. The problemsabout the true-set of historical rules, such as the problems of emptyness, infiniteness,equivalence and containment are proved to be undecidable.展开更多
XML has been used extensively in many applications as a de facto standard for information representation and exchange over internet. Huge volumes of data are organized or exported in tree-structured form and the desir...XML has been used extensively in many applications as a de facto standard for information representation and exchange over internet. Huge volumes of data are organized or exported in tree-structured form and the desired information can be got by traversing the whole tree structure using a twig pattern query. A new definition, Extended Solution Extension, is proposed in this paper to check the usefulness of an element from both forward and backward directions. Then a novel Extended Solution Extension based algorithm, TwigStack^＋, is also proposed to reduce the query processing cost, simply because it can check whether other elements can be processed together with the current one. Compared with existing methods, query evaluation cost can be largely reduced. The experimental results on various datasets indicate that the proposed algorithm performs significantly better than the existing ones.展开更多
In this systems paper,we present MillenniumDB:a novel graph database engine that is modular,persistent,and open source.MillenniumDB is based on a graph data model,which we call domain graphs,that provides a simple abs...In this systems paper,we present MillenniumDB:a novel graph database engine that is modular,persistent,and open source.MillenniumDB is based on a graph data model,which we call domain graphs,that provides a simple abstraction upon which a variety of popular graph models can be supported,thus providing a flexible data management engine for diverse types of knowledge graph.The engine itself is founded on a combination of tried and tested techniques from relational data management,state-of-the-art algorithms for worst-case-optimal joins,as well as graph-specific algorithms for evaluating path queries.In this paper,we present the main design principles underlying MillenniumDB,describing the abstract graph model and query semantics supported,the concrete data model and query syntax implemented,as well as the storage,indexing,query planning and query evaluation techniques used.We evaluate MillenniumDB over real-world data and queries from the Wikidata knowledge graph,where we find that it outperforms other popular persistent graph database engines(including both enterprise and open source alternatives)that support similarqueryfeatures.展开更多
文摘Aim To develop a heterogeneous database united system(HDBUS)that combines the local database of Oracle, Sybase and SQL server distributed on different server into a global database,and supports the global transaction management and parallel query over the Intranet Methods In the designing and implementation of HDBUS two important concepts heterogeneous tables join. Results and Conclu- tion The first concept can be used to process the parallel query of multiple database server, the second one is the key technology of heterogeneous is the key technology of heterogeneous distribute database.
文摘This paper defines a new kind of rule, probability functional dependency rule. The functional dependency degree can be depicted by this kind of rule. Five algorithms, from the simple to the complex, are presefited to mine this kind of rule in different condition. The related theorems are proved to ensure the high efficiency and the correctness of the above algorithms.
基金Project supported by the National Natural Science Foundation of China.
文摘<正> To process the data with strong historical features, such as data in earthquake research,weather forecast, medical records and census, a new mathematical model of historical datasystem is proposed. This model can be characterized as ' relational database with timemark + histotical rule base = historical database', and it is easy to implement. The formaldescription of historical database and a special class of historical rules-premonitory de-pendency (abbreviated as PD)-are discussed, the poperties and inference axioms of PDare investigated. The soundness and completeness of the axioms are proved. The problemsabout the true-set of historical rules, such as the problems of emptyness, infiniteness,equivalence and containment are proved to be undecidable.
基金Supported by the National Natural Science Foundation of China (60573091, 60273018)
文摘XML has been used extensively in many applications as a de facto standard for information representation and exchange over internet. Huge volumes of data are organized or exported in tree-structured form and the desired information can be got by traversing the whole tree structure using a twig pattern query. A new definition, Extended Solution Extension, is proposed in this paper to check the usefulness of an element from both forward and backward directions. Then a novel Extended Solution Extension based algorithm, TwigStack^＋, is also proposed to reduce the query processing cost, simply because it can check whether other elements can be processed together with the current one. Compared with existing methods, query evaluation cost can be largely reduced. The experimental results on various datasets indicate that the proposed algorithm performs significantly better than the existing ones.
基金supported by ANID-Millennium Science Initiative Program-Code ICN17_002。
文摘In this systems paper,we present MillenniumDB:a novel graph database engine that is modular,persistent,and open source.MillenniumDB is based on a graph data model,which we call domain graphs,that provides a simple abstraction upon which a variety of popular graph models can be supported,thus providing a flexible data management engine for diverse types of knowledge graph.The engine itself is founded on a combination of tried and tested techniques from relational data management,state-of-the-art algorithms for worst-case-optimal joins,as well as graph-specific algorithms for evaluating path queries.In this paper,we present the main design principles underlying MillenniumDB,describing the abstract graph model and query semantics supported,the concrete data model and query syntax implemented,as well as the storage,indexing,query planning and query evaluation techniques used.We evaluate MillenniumDB over real-world data and queries from the Wikidata knowledge graph,where we find that it outperforms other popular persistent graph database engines(including both enterprise and open source alternatives)that support similarqueryfeatures.
