Amit P. Sheth and James A. Larson. Federated Database Systems for Managing Distributed, Heterogeneous, and Autonomous Databases. ACM Computing Surveys, 22(3):183-236, 1990.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....this is not possible [1] That is, in an MDBS a global checkpoint can not be made without violating the autonomy of local DBMSs. The issue of local DBMS autonomy has been extensively studied [13, 16, 60] Typical autonomy types are design, execution, communication (association) and control [4, 5, 47, 60]. Design autonomy implies that the DBMSs can not be redesigned to fit the needs of the MDBS. No changes can be made to a local DBMS. Execution autonomy means that each DBMS has complete control over the execution of its transactions. Each DBMS has the ability to execute, commit, and abort their ....

Amit P. Sheth and James A. Larson. Federated database systems for managing distributed, heterogeneous, and autonomous databases. ACM Computing Surveys, 22(3):183--236, 1990.

....in a given organization can be very large; on the other hand a particular application is most likely to use only a small subset of these databases. Multidatabase or federated database systems provide for the interoperability of autonomous database systems without requiring their global integration [MH80, LMR90, SL90, SC94, PS95]. In order to answer queries in multidatabase systems three distinct processes need to be performed by the user, database administrator, and or system as shown in Figure 1. The Schema Integration includes a possible schema transformation step, followed by correspondence identification, and an ....

Amit Sheth and James Larson. Federated database systems for managing distributed heterogeneous, and autonomous databases. ACM Computing Surveys, 22(3):183--236, September 1990.

....efficiently access the desired information. We are focusing on the problems of how to organize, manipulate, and learn about large quantities of data. Research in databases has also focused on building integrated or federated systems that combine information sources [Landers and Rosenberg, 1982, Sheth and Larson, 1990] The approach taken in these systems is to first define a global schema, which integrates the information available in the different information sources. However, this approach is unlikely to scale to the large number of evolving information sources (e.g. the Internet) since building an ....

Amit P. Sheth and James A. Larson. Federated database systems for managing distributed, heterogeneous, and autonomous databases. A CM Computing Surveys, 22 (3):183-236, 1990.

....[20] A federated database system approach is chosen instead of the sequential organization preferred by other authors [3, 4, 11] Assume that data are managed in a system of cooperating autonomous databases that are related through a set of generalization functions. The system is federated [15] in that the databases store di#erent versions of the same information and cooperate by exchanging information. The generalization functions define how data may flow from one database to another and imposes a graph structure on the system of databases. A database can have many input data streams ....

Amit P. Sheth and James A. Larson. Federated database systems for managing distributed, heterogeneous, and autonomous databases. ACM Computing Surveys, 22(3):183--236, 1990.

....systems more flexible since they make it easier to substitute different classes into a given cooperation pattern. They also make systems more understandable since contracts help to make system architecture explicit and manipulable. Genericity has also been applied to Federated Database Systems [51] (an area close to Cooperative Information Systems) Generic mechanisms are offered to describe a federated database schema in terms of the external schemas of the various databases constituting the federation: one formally describes an integration contract between the various databases in terms ....

Amit P. Sheth and James A. Larson, "Federated Database Systems for Managing Distributed Heterogeneous, and Autonomous Databases," ACM Computing Surveys, vol. 22, no. 3, September 1990, pp. 183-236.

....for e ectively answering queries posed to the data integration system in this case. 1 Introduction Integrating heterogeneous data sources is a fundamental problem in databases, which has been studied extensively in the last two decades both from a formal and from a practical point of view [3, 29, 30, 25, 10, 20]. Recently, mostly driven by the need to integrate data sources on the Web, much of the research on integration has focussed on so called data integration [19, 31, 20] Data integration is the problem of combining the data residing at di erent sources, and providing the user with a uni ed view of ....

Amit P. Sheth and James A. Larson. Federated database systems for managing distributed, heterogeneous, and autonomous databases. ACM Computing Surveys, 22(3):183-236, 1990.

....or business logic layer. One way to classify distributed database systems is based on the degree of certain characteristics [20] The degree of autonomy of the component databases plays an important role in the design of the distributed database. There are several different types of autonomy [19]: 12 Design autonomy The component database system has control over the design of the database, such as what data is included and how it is named, the data model used, the semantics of the data items, integrity constraints imposed, and what operations are supported. Execution autonomy The ....

....platforms, operating systems, or network protocols used by different DBMSs. These types of differences, however, are usually handled by the client server infrastructure. Other types of heterogeneity are caused by differences in the distributed database systems. These can be classified as follows [19]: Structural and constraint differences Different data models represent data differently, and may allow different structures (such as generalization) which may be difficult to translate between models. Also, the constraints supported by some models may not be representable easily in other ....

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Amit P. Sheth and James A. Larson. Federated database systems for managing distributed, heterogeneous, and autonomous databases. ACM Computing Surveys, 22(3), September 1990.

....model and a uniform representation. Standardized data models and schemas, e.g. the AP214 [ISO94] of STEP [ISO97] 2 are very important because of their international acceptance. The common and particularly transparent access of data has been realized either by an FDBS (federated database system) [SL90] or an additional software layer called middleware. The next step was the awareness that it is not enough to integrate the systems only via their database interfaces. A huge number of applications do not allow direct access to their databases. Examples for these systems are ERP 1 software like ....

Amit P. Sheth, James A. Larson (1990). Federated Database Systems for Managing Distributed, Heterogeneous, and Autonomous Databases. ACM Computing Surveys, 22 (3): 183-236.

....the data masses, and web crawlers and information mining systems sh for useful pieces of data. Unfortunately, all those information providers dioeer quite a lot, concerning data models, data structures, reliability, etc. Approaches for resolving these dioeerences are federated database systems [SL90] and mediators [Wie92] 1 We are interested especially in resolving dioeerences of the data structures, given a xed application schema and an extremely heterogeneous, rapidly changing environment. While the raw data comes in proprietary data structures or in semi structured format, we want to ....

Amit P. Sheth and James A. Larson. Federated database systems for managing distributed, heterogeneous, and autonomous databases. ACM Computing Surveys, 22(3):183236, September 1990.

....be called within our computational environment to generate data. The extension of SIMS to OODB s and flat files would appear to be straightforward, and is planned in the near future. 6 Related Work There are a variety of approaches to handling distributed, heterogeneous, and autonomous databases [Sheth and Larson, 1990, Reddy et al. 1989] Of these approaches, the tightlycoupled federated systems are the most closely related to SIMS in that they attempt to support total integration of all information sources in the sense that SIMS provides. However, building tightly coupled federated system requires ....

Amit P. Sheth and James A. Larson. Federated database systems for managing distributed, heterogeneous, and autonomous databases. ACM Computing Surveys, 22(3):183--236, 1990. 29

....data will be accessible as one dataset. 2.4 General Introduction Basic Concepts and Denitions There has been done a lot of research on interoperability of autonomous databases and architectures for such systems. However, we will mainly follow the classications and taxonomy from Sheth and Larson [SL90] because their work gives a general overview that seems to cover the majority of the literature on the subject (e.g. BHP92, HM85, LMR90, NSGS89] Also, most of the literature in recent years seems to refer to Sheth and Larson [SL90] as a basis for their work. As mentioned above, a database ....

.... follow the classications and taxonomy from Sheth and Larson [SL90] because their work gives a general overview that seems to cover the majority of the literature on the subject (e.g. BHP92, HM85, LMR90, NSGS89] Also, most of the literature in recent years seems to refer to Sheth and Larson [SL90] as a basis for their work. As mentioned above, a database system (DBS) can vary in its level of distribution. At the one end a DBS can be centralized and residing on one computer system. At the other end a DBS can be distributed and residing on multiple computer systems. The multidatabases are ....

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Amit P. Sheth and James A. Larson. Federated Database Systems for Managing Distributed, Heterogeneous and Autonomous Databases. ACM Computing Surveys, 22(3):183236, September 1990.

....component is responsible for managing the parsing of type definitions into PolySPINner s language independent intermediate representation. In its current form, this intermediate representation 6 As noted in section 2. 3, full discussion of database merging issues, such as semantic heterogeneity [SL90] is beyond the scope of this paper. t 1 t 2 , t n Multi language Types Parser language x language y Parser Matcher Generator communication medium match criteria match specification abstract syntax trees t 1 t 2 , t n Polylingual Types PolySPINner ....

Amit P. Sheth and James A. Larson. Federated database systems for managing distributed, heterogeneous, and autonomous databases. ACM Computing Surveys, 22(3):183--236, September 1990. 8

....sets. 2.2 Resolving Inter Agent Inconsistencies [CO93] argue that the traditional federation model involving an orchestrating layer above the information systems (agents) to resolve inconsistencies is unrealistic, in general. Where agents representations of semantically compatible concepts ([SL90]) are heterogeneous, it is likely that at least one of the agents will need be modified to facilitate interoperability. The extent of these modifications must be constrained by the following considerations : ffl cascading agent modification : An agent may require modifications in the agents with ....

Amit Sheth and James Larson. Federated database systems for managing distributed, heterogeneous, and autonomous databases. ACM Computing Surveys, 22(3):183--236, September 1990.

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Amit P. Sheth and James A. Larson. Federated Database Systems for Managing Distributed, Heterogeneous, and Autonomous Databases. ACM Computing Surveys, 22(3):183-236, 1990.

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Amit P. Sheth and James A. Larson. Federated database systems for managing distributed, heterogeneous, and autonomous databases. ACM Computing Surveys (CSUR), 22(3):183--236, 1990.

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Amit P. Sheth and James A. Larson. Federated database systems for managing distributed, heterogeneous, and autonomous databases. ACM Computing Surveys (CSUR), 22(3):183--236, 1990.

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Amit P. Sheth and James A. Larson. Federated database systems for managing distributed, heterogeneous, and autonomous databases. ACM Computing Surveys (CSUR), 22(3):183--236, 1990.

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Amit P. Sheth and James A. Larson. Federated database systems for managing distributed, heterogeneous, and autonomous databases. ACM Computing Surveys, 22(3):183--236, 1990.

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Amit P. Sheth and James A. Larson. Federated database systems for managing distributed heterogeneous and autonomous databases. ACM Computing Surveys, 22(3):183-236, September 1990.

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Amit P. Sheth and James A. Larson. Federated database systems for managing distributed, heterogeneous, and autonomous databases. ACM Computing Surveys, 22(3):183--236, 1990.

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Amit P. Sheth and James A. Larson. Federated database systems for managing distributed, heterogeneous, and autonomous databases. ACM Computing Surveys (CSUR), 22(3):183--236, 1990.

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Amit P. Sheth and James A. Larson, "Federated Database Systems for Managing Distributed, Heterogeneous, and Autonomous Databases", ACM Computing Surveys 22(3), Sept. 1990.

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Amit P. Sheth and James A. Larson. Federated database systems for managing distributed heterogeneous and autonomous databases. ACM Computing Surveys, 22(3):183-236, September 1990.

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Amit Sheth and James Larson. Federated database systems for managing distributed heterogeneous, and autonomous databases. ACM Computing Surveys, 22(3):183--236, September 1990.

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Amit P. Sheth and James A. Larson. Federated Database Systems for Managing Distributed, Heterogeneous, and Autonomous Databases. ACM Computing Surveys, 22(3):183-236, 1990.

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