It is often necessary to develop database applications with no prior knowledge of the structure of the database. Such applications may be referred to as generic applications, and often they can be required to manipula...
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ISBN:
(纸本)3540440879
It is often necessary to develop database applications with no prior knowledge of the structure of the database. Such applications may be referred to as generic applications, and often they can be required to manipulate multiple (possibly heterogenous) databases across a network. We explore the problems of developing generic applications for the current standard of object-oriented databases, and describe the properties that are needed to build a truly generic application.
This paper describes a method for designing object-oriented databases and a tool to implement it. The method provides the designer a set of rules which allows the design of an object-oriented database from specificati...
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XML has emerged as the universal format for data exchange and is being widely used in technical documentation of manufacturing companies, book publishing, and Web publishing. It is also being used in contexts that are...
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ISBN:
(纸本)0769523153
XML has emerged as the universal format for data exchange and is being widely used in technical documentation of manufacturing companies, book publishing, and Web publishing. It is also being used in contexts that are mission-critical, such as banking and e-commerce. One of the main reasons for the popularity of XML is its semi-structured nature and the flexibility of its component parts. Schemaless XML documents, which do not have a schema or Document Type Definition (DTD), have the highest level of flexibility, as they are not bound to any kind of structure. However, support for schemaless XML documents in the major relational and object-oriented databases is limited to storing each of them as a CLOB (Character Large object). This kind of storage requires the usage of associative search criteria to query the document, and does not support piecewise update and multiple document queries. In this research, we developed a middleware layer over an Oracle DBMS to support the storage, retrieval, query and update of schemaless XML documents. We also propose an algorithm by which we can store the logical structure of the XML document in addition to storing its content. The final part of this paper presents an algorithm that can rebuild XML documents by using the stored logical structures and the content of the XML documents. The rebuilt XML document is a well-formed document and is similar to the original document.
One of the differences between relational and object-oriented databases (OODB) is that attributes in OODB can be of a collection type (e.g. sets, lists, arrays, bags) as well as a simple type (e.g. integer, string). C...
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ISBN:
(纸本)0818683082
One of the differences between relational and object-oriented databases (OODB) is that attributes in OODB can be of a collection type (e.g. sets, lists, arrays, bags) as well as a simple type (e.g. integer, string). Consequently, explicit join queries in OODB may be based on collection attributes, One form of collection join queries in OODB is "collection-equi join queries", where the joins are based on collection attributes and the queries check for an equality of both collection operands. Our previous work [7] describes "Parallel Double Sort-Merge" algorithm for collection-equi join queries. Since the publication, we realize that we have overlooked the complexity of collection merging in the algorithm. in this paper We not only present alternative solutions relating to the collection merging problem, but also introduce a new algorithm called "Parallel Sort-Hash" algorithm. The two algorithms play an important role in parallel object-oriented query processing. due to their superiority over the conventional join methods through relational division and intersection operators.
We present in this paper three dynamic clustering techniques for object-oriented databases (OODBs). The first two, Dynamic, Statistical & Tunable Clustering (DSTC) and StatClust, exploit both comprehensive usage s...
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ISBN:
(纸本)3540416641
We present in this paper three dynamic clustering techniques for object-oriented databases (OODBs). The first two, Dynamic, Statistical & Tunable Clustering (DSTC) and StatClust, exploit both comprehensive usage statistics and the inter-object reference graph. They are quite elaborate. However, they are also complex to implement and induce a high overhead. The third clustering technique, called Detection & Reclustering of objects (DRO), is based on the same principles, but is much simpler to implement. These three clustering algorithm have been implemented in the Texas persistent object store and compared in terms of clustering efficiency (i.e., overall performance increase) and overhead using the object Cluslering Benchmark (OCB). The results obtained showed that DRO induced a lighter overhead while still achieving better overall performance.
A technique for transparent access to persistent objects is presented, which is a key technique for achieving the seamless integration of object-oriented databases and programming languages, in the condition of keepin...
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The paper focuses on the indexing on non-primitive (complex) values of attributes in an object management system. A new index structure for indexing on set (multivalued) attributes is proposed. This structure is based...
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ISBN:
(纸本)0818681306
The paper focuses on the indexing on non-primitive (complex) values of attributes in an object management system. A new index structure for indexing on set (multivalued) attributes is proposed. This structure is based an a partial order imposed on the values of the indexed attribute, which are subsets of a set of primitive values. It is shown that the proposed index allows the system to efficiently perform typical set operators that are postulated to be applied in object query languages (is-equal, is-subset, is-superset), without performing any costly operations on lists of object identifiers that would be necessary in traditional index structures. The new index structure called partial-order tree, is described and algorithms performing the set operators are outlined.
object-oriented database systems (ooDBMSs) are supposed to offer at least the functionality available in commercial relational DBMSs of today. One important consequence of this is that they have to provide a separatio...
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Horizontal partitioning (HP) technique is a logical database design technique first developed for distributed relational (record structured) databases. Though the main objective of HP is to reduce irrelevant data acce...
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object-oriented databases has rich semantics, which enables the definition of various relationships among objects. Sharing levels and composition types necessitate the definition of whether, and to which extent, shoul...
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