Clustering is an effective mechanism for retrieving complex objects. Many object-oriented database management systems have suggested variant clustering schemes to improve their performance. Two issues may compromise t...
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Although object-oriented database systems offer more powerful modeling capability than relational database systems, their performance suffers from the increased complexity in the data model. Recently, a lot of researc...
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ISBN:
(纸本)0889863237
Although object-oriented database systems offer more powerful modeling capability than relational database systems, their performance suffers from the increased complexity in the data model. Recently, a lot of research has been directed to mitigating this problem by building indexes over single classes, class hierarchies or nested object hierarchies. In this paper, we propose a new indexing method. It is based on the technique of signature files, but differs from the existing methods in two aspects: (1) all the signature files are organized into a hierarchy to filter irrelevant data as early as possible;(2) a signature file itself is stored as a tree structure (called a signature tree) to speed up the signature scanning. Together with the concept of query signature hierarchies, this technique reduces the search space dramatically and therefore improves significantly the time complexity of query evaluation.
In the new applications such as OIS, CAD/CAM, and AI, it is required to support not only fixed Is-A and Part-Of relationships but also various dynamic relationships including complicate constraints. However, existing ...
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Query graph (QG) is an easy-to-use visual query language which facilitates formulating a query. Unlike relational databases, in object-oriented databases (OODBs), the basic entity of QG, i.e. a class, may consist of s...
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In this paper, an analysis of the schema evolution process in objectorienteddatabases is made using an objectoriented data model that supports temporal features and versions definition - the Temporal Versions Model...
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This paper discusses function materialization for features of objects in object-oriented databases, and identifies its role in design databases. Drawbacks with the present approaches are discussed and a new approach t...
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Many applications of object-oriented Database systems demand high performance and require longer duration transactions. These requirements are contrary to one another. Two trends in modern systems can help improve the...
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object-oriented databases (OODBs) are believed to more naturally reflect the behavior and organization of real world objects. However, OODBs are mostly concerned about only the static aspects of object modeling. While...
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In this article, we propose a method of object identification in the state of fuzzy object-oriented database schema based on different notions of fuzzy object functional dependencies. Here, fuzzy object functional dep...
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It is claimed that object-oriented databases overcome many of the limitations of the relational data model especially by generalizing the notion of object identification. A clear distinction between objects and values...
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