Optimization of object queries containing path expressions
نویسندگان
چکیده
منابع مشابه
On the Optimization of Queries Containing Regular Path Expressions
One of the main characteristics of object-oriented database management systems is the explicit representation of relationships between objects. A simple example for a query addressing these relationships arises, if we assume the object types Company , and Division with the relationship has division from Company to Division. In this case a query might ask for the companies which have a division ...
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Query processing remains one of the important challenges of Object-Oriented Database Management Systems. Cost based query optimization involves creating alternative executing plans for a given query and executing the least costly one within a cost model framework. In Object-Oriented Database Management Systems (OODBMSs) objects may store references to other objects (precomputed joins), and path...
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Path expressions a central ingredient of query languages for object oriented databases are currently used as a purely navigational vehicle We argue that this does not fully exploit their potential expressive power as a tool to specify connections between objects In particular a user should not be required to specify a path to be followed in full but rather should provide enough information so t...
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Query optimization techniques are dependent upon the query model and language. The query model, in turn, is based on the data (or object) model since it defines the access primitives which are used by the query model. These primitives determine the power of the query model. Object-oriented languages allow expressing queries explicitly in the code, which are optimized using the query optimizatio...
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Query optimization is the process of finding the best or rather a reasonably efficient execution plan, thus by minimizing the time of query evaluation & the cost of evaluation to the level accepted by user. When a query jointly addresses very large and small collections, the iteration caused by query operator is driven by large collection and in each cycle a subquery which depends on an element...
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ژورنال
عنوان ژورنال: Journal of Computer Science and Cybernetics
سال: 2012
ISSN: 1813-9663,1813-9663
DOI: 10.15625/1813-9663/25/3/574