Y. Papakonstantinou, S. Abiteboul, and H. Garcia-Molina. Object fusion in mediator systems. In Proc. of VLDB, pages 413--424, Bombay, India, 1996.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....involved in the fusion query of interest. name, and names can be misspelled. The most practical way to cope with these problems is to develop a unique canonical form for the merge attribute (and hopefully for the rest of the attributes too) Then the wrapper or the mediator uses mapping functions [54] to translate data from the source into the canonical form and translate queries with canonical values into queries that use source specific values. Unfortunately, canonical forms are not always applicable (e.g. consider the case of misspellings. However, to deal with a more tractable problem, ....

Y. Papakonstantinou, S. Abiteboul, H. Garcia-Molina. Object Fusion in Mediator Systems. In Proc. VLDB Conference, 1996.

....DB Source DB Source OLAP System Reports Figure 2.1 Source databases can be heterogeneous with respect to their data representation and to the data itself. Data integration is an important research area that treat this problem. Some publications that concentrate on source heterogeneity are [Pap96][Lev96] which consider in particular the web sources. In many projects as H20, TSIMMIS, DWQ, strong attention is paid to data integration [Hull96] Hull97] Pap96] Cal99] In order to translate heterogeneous data models to a common model, some authors propose the use of wrappers [Lab97] Tork97] ....

....Data integration is an important research area that treat this problem. Some publications that concentrate on source heterogeneity are [Pap96] Lev96] which consider in particular the web sources. In many projects as H20, TSIMMIS, DWQ, strong attention is paid to data integration [Hull96] Hull97][Pap96][Cal99] In order to translate heterogeneous data models to a common model, some authors propose the use of wrappers [Lab97] Tork97] which encapsulate data sources and mediate between them and the rest of the system. Data transformation layer involves a wide range of transformations that have ....

Y. Papakonstantinou, S. Abiteboul, H. Garcia-Molina. Object Fusion in Mediator Systems. VLDB 1996.

....databases. Moreover, in UniSQL M they classified structural conflict problems in schema integration process and provided resolution techniques for these structural conflicts. However, this work was for database integration, thus integration target was limited in database schema. TSIMMIS[7] adopted the mediator architecture, allowing user to create a hierarchy of wrappers and mediators that talk to one another. TSIMMIS components communicated among themselves using a data model named OEM(Object Exchange Model) which was a semistructured data model that used object labels to ....

Y. Papakonstantinou, S. Abiteboul, H. Garcia-Molina, "Object Fusion in Mediator Systems", proc. Of Int'l Conference on VLDB, pp. 413-424, 1996.

....systems use CDM (Common Data Model) to redefine various schema definition represented with heterogeneous data models. The CDM can be OO data model, semistructured data model, and so on. Some integration systems use XML DTD as a CDM. Because XML has semi structured data model like an OEM in TSIMMIS[1], and it is a standard markup language to define user own data structure, it can be used as a CDM. However, XML DTD, schema for XML data or documents, has some limitations to represent all of data models. These limitations are: 1) XML DTD does not support various data types such as integer, ....

Y. Papakonstantinou, S. Abiteboul, H. Garcia-Molina "Object Fusion in Mediator Systems", Proc. Of Int'l Conference on VLDB, pp. 413-424, 1996.

.... databases, partially labeled object s 1 Introduction The common accepted architecture in many projects providing integrated access to heterogeneous information stored in conventional databases, file systems, the Web, and legacy systems, consists of two important layers: wrappers and mediators [9]. Wrappers convert data from each source into a common model and also provide a common query language. Mediators perform object fusion. To represent data on the wrapper layer, schemaless object oriented models were developed. The most famous of them is the OEM (Object Exchange Model) data model ....

....language. Mediators perform object fusion. To represent data on the wrapper layer, schemaless object oriented models were developed. The most famous of them is the OEM (Object Exchange Model) data model which was designed in Stanford and was used in Tsimmis (a project for data integration) [9,10,11,13] and in Lore (a project for managing semi structured data) 2,11 ] By means of OEM one can represent semistructured data such as HTML, XML or Latex documents, and also data from well structured databases [ 1,12] In the Web, however, there are also data which do not have structure of labeled ....

Papakonstantinou Y., Abiteboul S., Garcia-Molina It., Object Fusion in Mediator Systems, Proceedings of the Twenty-Second Conference on VLDB, pp. 413-424, 1996.

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Y. Papakonstantinou, S. Abiteboul, and H. Garcia-Molina. Object Fusion in Mediator Systems. In Proc. of VLDB, 1996.

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Y. Papakonstantinou, S. Abiteboul, and H. Garcia-Molina. Object Fusion in Mediator Systems. In Proc. of VLDB, 1996.

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Y. Papakonstantinou, S. Abiteboul, and H. Garcia-Molina. Object Fusion in Mediator Systems. In Proc. of VLDB, 1996.

....back to the server if it needs one of the missing parts. The tokens contain information needed for tne Mediator to produce the missing parts. The effects of the on demand, navigation driven execution model are lower memory footprint and reduced data exchanges from the data sources to the Mediator [32]. A partial result has multiple lists of elements that are incomplete, as in Figure 2(a) from where navigation can continue because of the information encoded in the tokens. For example, the Mediator may have exported the partial result of Figure 2(a) If the client navigates to the second child ....

....fragment. A key challenge in optimizing navigation driven query evaluation is the choice of the size and shape of fragments produced. At the one extreme, one may choose each node of the data model to be a fragment and encode the relevant token in the node itself. This approach, described in [32], is elegant but it is very inefficient in the number of round trips that will be needed between the client and the server. Moreover, it penalizes the server with unacceptable overhead in creating tokens. Instead, the Mediator employs a complex algorithm for client server interaction control ....

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Y. Papakonstantinou, S. Abiteboul, and H. Garcia-Molina. Object fusion in mediator systems. In Proc. VLDB Conf., 1996.

.... Wrappers in the System Joachim Hammer, Hector Garcia Molina, Svetlozar Nestorov, Ramana Yerneni, Marcus Breunig, Vasilis Vassalos Department of Computer Science Stanford University Stanford, CA 94305 9040 E mail: fjoachim,hector,evtimov,yerneni,vassalosg db.stanford.edu http: www db.stanford.edu tsimmis 1 Overview In order to access information from a variety of heterogeneous information sources, one has to be able to translate queries and data from one data model into another. This ....

....on these observations, wehave developed a wrapper implementation toolkit [7] for quickly building wrappers. The toolkit contains a library for commonly used functions, such as for receiving queries from the application and packaging results. It also This work was supported by ARPAContract F33615 931 1339, by the Anderson FacultyScholar Fund, by the Center for Integrated Systems at Stanford University, and byequipment grants from Digital Equipment Corporation and IBM Corporation. The US Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding ....

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Y. Papakonstantinou, H. Garcia-Molina, and S. Abiteboul. Object fusion in mediator systems. In Proceedings of the International ConferenceonVery Large Databases, Bombay, India, Septyember 1996.

....data arises because the integrated objects may be based on complimentary, sometimes conflicting, and often dynamic information from multiple sources, forcing the integrator to filter, merge, or omit certain fields when performing the integration. The goal of the Tsimmis project at Stanford [4, 7, 11, 13] is to provide integrated access to a wide variety of heterogeneous data sources (e.g. databases, object stores, knowledge bases, digital libraries) including sources containing semistructured data (e.g. WWW, file system) In this paper, we presenttheTsimmis approach to managing semistructured ....

Y. Papakonstantinou, H. Garcia-Molina, and S. Abiteboul. Object fusion in mediator systems. In Proceedings of the International ConferenceonVery Large Databases, pages 234--245, Bombay, India, September 1996.

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Y. Papakonstantinou, S. Abiteboul, and H. Garcia-Molina. Object fusion in mediator systems. In Proc. of VLDB, pages 413--424, Bombay, India, 1996.

No context found.

Y. Papakonstantinou, S. Abiteboul, and H. Garcia-Molina. Object fusion in mediator systems. In Proc. of VLDB, pages 413--424, Bombay, India, 1996.

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Y. Papakonstantinou, S. Abiteboul, and H. GarciaMolina. Object fusion in mediator systems. In Proc. of SIGMOD, pages 413--424, 1996.

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Papakonstantinou, Y, S. Abiteboul, and H. Garcia-Molina (1996) "Object Fusion in Mediator Systems." In Intl. Conf. on Very Large Data Bases (VLDB).

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Y. Papakonstantinou, S. Abiteboul, H. Garcia-Molina, 1996. Object fusion in mediator systems. Proceedings of 22nd International Conference on Very Large Databases (VLDB'96).

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Y. Papakonstantinou, S. Abiteboul, and H. Garcia-Molina. Object Fusion in Mediator Systems. VLDB Conference, 1996.

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Papakonstantinou, Y., Abiteboul, S., and Garcia-Molina, H. 1996. \Object Fusion in Mediator Systems", In Proc. of the Int. Conf. on Very Large Databases, September.

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Y. Papakonstantinou, S. Abiteboul, and H. Garcia-Molina. Object fusion in mediator systems. In Proceedings of the 22nd International Conference on Very Large Databases, pages 413--424, 1996.

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Y. Papakonstantinou, S. Abiteboul, and H. Garcia-Molina. Object fusion in mediator systems. In VLDB Int. Conf., Bombay, India, September 1996.

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Y. Papakonstantinou, S. Abiteboul, and H. Garcia-Molina. Object fusion in mediator systems. In Proceedings of the 22nd International Conference on Very Large Databases, pages 413--424, 1996.

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Y. Papakonstantinou, S. Abiteboul, and H. Garcia-Molina. Object Fusion in Mediator Systems. VLDB Conference, 1996.

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Y. Papakonstantinou, S. Abiteboul, Object fusion in mediator systems, in: Proceedings of the Conference on Very Large Data Bases, Bombay, India, 1996.

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Papakonstantinou, Y., Abiteboul, S., and Garcia-Molina, H. 1996. \Object Fusion in Mediator Systems", In Proc. of the Int. Conf. on Very Large Databases, September.

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Y. Papakonstantinou, S. Abiteboul, and H. Garcia-Molina. Object fusion in mediator systems. In Proc. of the 22nd Intl. Conf. on Very Large Data Bases (VLDB), pages 413--424, 1996.

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