[1990] Proceedings. Sixth International Conference on Data Engineering

5-9 Feb. 1990

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Displaying Results 1 - 25 of 66
  • ViewSystem: integrating heterogeneous information bases by object-oriented views

    Publication Year: 1990, Page(s):2 - 10
    Cited by:  Papers (37)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (765 KB)

    In order to overcome practical integration problems, ViewSystem, an object-oriented programming environment with dedicated integration operators by which syntactically and semantically heterogeneous information can be integrated incrementally, has been developed. ViewSystem provides an object-oriented query language and a method language with universal computational power and a distinguished set o... View full abstract»

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  • Multimedia objects models for synchronization and databases

    Publication Year: 1990, Page(s):20 - 27
    Cited by:  Papers (9)  |  Patents (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (718 KB)

    The authors propose a technique for formally specifying and modeling the temporal composition of multimedia data. The proposed model is based on timed Petri nets and the logic of temporal intervals. A strategy based on the inter media timing relationships established by the proposed modeling tool is presented for constructing a database schema to facilitate data storage and retrieval of data eleme... View full abstract»

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  • Concurrency control using locking with deferred blocking

    Publication Year: 1990, Page(s):30 - 36
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (611 KB)

    The concurrency control method employed can be critical to the performance of transaction processing systems. The conventional locking scheme tends to suffer from the blocking phenomenon. The proposed scheme reduces the blocking probability by deferring the blocking behavior of transactions to the later stages of their execution. The transaction execution can then be divided into a nonblocking pha... View full abstract»

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  • A paradigm for concurrency control in heterogeneous distributed database systems

    Publication Year: 1990, Page(s):37 - 46
    Cited by:  Papers (27)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (821 KB)

    A heterogeneous distributed databases system (HDDBS) is a system which integrates preexisting databases to support global applications accessing more than one database. An outline of approaches to concurrency control in HDDBSs is presented. The top-down approach emerges as a viable paradigm for ensuring the proper concurrent execution of global transactions in an HDDBS. The primary contributions o... View full abstract»

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  • Access invariance and its use in high contention environments

    Publication Year: 1990, Page(s):47 - 55
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (774 KB)

    Various factors suggest that data contention may be of increasing significance in transaction processing systems. One approach to this problem is to run transactions twice, the first time without making any changes to the database. Benefits may result either from data prefetching during the first execution or from determining the locks required for purposes of scheduling. Consideration is given to... View full abstract»

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  • A rule-based language for deductive object-oriented databases

    Publication Year: 1990, Page(s):58 - 67
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (861 KB)

    A deductive rule-based language for object-oriented databases is presented. A deductive rule in this language derives new patterns of associations among objects of some selected classes if these objects fall in certain 'base' on other derived patterns. The patterns of object associations derived by a rule are held in a subdatabase whose intention consists of some selected classes and their associa... View full abstract»

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  • Supporting universal quantification in a two-dimensional database query language

    Publication Year: 1990, Page(s):68 - 75
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (577 KB)

    A technique for specifying universal quantification and existential quantification (combined with negation) in a two-dimensional graphical database query language is proposed. Unlike other approaches that provide set operators to simulate universal quantification, this technique allows a direct representation of universal quantification. The authors present syntactic constructs for specifying univ... View full abstract»

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  • A temporal model and query language for ER databases

    Publication Year: 1990, Page(s):76 - 83
    Cited by:  Papers (19)  |  Patents (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (643 KB)

    A temporal extension to an extended ER (entity-relationship) model is proposed. The concept of life span for entities and relationships is incorporated in the ER model. Also specified is a temporal query and update language which is an extension of the GORDAS language. The concepts of temporal Boolean expressions, temporal selection, and temporal projection are introduced, and their use in the que... View full abstract»

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  • Object views: Extending the vision

    Publication Year: 1990, Page(s):86 - 93
    Cited by:  Papers (29)  |  Patents (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (719 KB)

    A mechanism for producing views in an object-oriented system is presented. The results are analogous to database views in traditional database systems, except that the object views presented hide or expose methods as well as data. The mechanism is based on the object model's built-in facilities for defining data and procedural abstractions and for constructing new types and objects. It uses the ty... View full abstract»

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  • Alternatives in complex object representation: a performance perspective

    Publication Year: 1990, Page(s):94 - 102
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (782 KB)

    With database systems finding wider use in CAD, office information systems, and logic programming applications, the importance of efficiently representing and manipulating complex objects is growing. In this study a classification of the alternatives for representing complex objects is examined. Consideration is given to the performance aspects of one representation technique based on object ident... View full abstract»

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  • Representing processes in the extended entity-relationship model

    Publication Year: 1990, Page(s):103 - 110
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (721 KB)

    Although closely related, functional and structural aspects of information systems are usually modeled independently of each other. The author proposes to combine functional and structural modeling into an integrated design methodology. He chooses for this purpose two popular and widely used models, the data-flow-oriented functional model and the extended entity-relationship (EER) data model. Sinc... View full abstract»

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  • Serializability in object-oriented database systems

    Publication Year: 1990, Page(s):112 - 120
    Cited by:  Papers (8)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (784 KB)

    In an object-oriented database the objects are encapsulated, that is, objects are only accessible by methods defined in the database system. The definition of object-oriented serializability takes advantage of the semantics and of the nesting of the methods. Therefore, a lower rate of conflicting accesses than with the conventional definition of serializability is achieved. Transactions of an obje... View full abstract»

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  • Parallelism in database production systems

    Publication Year: 1990, Page(s):121 - 128
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (645 KB)

    A study is made of the issues in parallelizing database production systems. Various kinds of parallelism possible in production systems are classified. Parallel execution of production systems leads to some subtle problems which, if not handled carefully, can cause altered execution semantics. The precise conditions that any parallel implementation of production systems must fulfil in order to be ... View full abstract»

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  • Performance evaluation of multiversion database systems

    Publication Year: 1990, Page(s):129 - 136
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (723 KB)

    A description is given of a detailed simulation study of the performance of multiversion database systems. The characteristics and the extent to which they provide performance benefits over their single-version counterparts are investigated. First, the structure of a software prototyping environment for the evaluation of distributed database systems is presented. Using this environment, the author... View full abstract»

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  • Generalization and a framework for query modification

    Publication Year: 1990, Page(s):138 - 145
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (676 KB)

    The rigidity and limited expressiveness of relational queries often require that a query be iteratively modified. An initial query is posed, and once it is discovered that the answer does not meet the additional constraints, which are not expressed in the relational query, it is necessary to modify the query in a way such that those constraints are satisfied. The aim of this work is to capture thi... View full abstract»

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  • A modular query optimizer generator

    Publication Year: 1990, Page(s):146 - 153
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (713 KB)

    An examination is made of existing rule-based optimizers, showing that they have significant limitations. A new approach to optimization based on the idea of modules is presented. An optimizer is divided into several interconnected modules. Each module has its own set of rewrite rules and can be implemented differently according to how the rules are used. This modular approach avoids the limitatio... View full abstract»

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  • A query algebra for object-oriented databases

    Publication Year: 1990, Page(s):154 - 162
    Cited by:  Papers (51)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (733 KB)

    An algebra that synthesizes relational query concepts with object-oriented databases is defined. The algebra fully supports abstract data types and object identity, while providing associative access to objects. The operations take an abstract view of objects and access typed collections of objects through the public interface defined for the type. The algebra supports access to relationships impl... View full abstract»

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  • Scheduling data redistribution in distributed databases

    Publication Year: 1990, Page(s):166 - 173
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (616 KB)

    In a distributed database system there is a need for periodic changes in data distribution due to such factors as changes in query patterns and network topology. A proper redistribution of data is necessary to provide acceptable system performance, as measured by the average execution time of transactions. The problem of properly scheduling data transfers in order to complete this redistribution p... View full abstract»

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  • Cost of distributed deadlock detection: a performance study

    Publication Year: 1990, Page(s):174 - 181
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (645 KB)

    A performance evaluation of two classes of distributed deadlock detection algorithms, namely, set-based and probe-based distributed deadlock detection algorithms, is presented. The performance evaluation is performed on a simulated distributed database by implementing the algorithms. The performance evaluation shows two main results. First, set-based algorithms outperform probe-based algorithms. S... View full abstract»

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  • Experimental evaluation of concurrent checkpointing and rollback-recovery algorithms

    Publication Year: 1990, Page(s):182 - 189
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (725 KB)

    The performance of two distributed checkpointing and recovery algorithms, the synchronous checkpointing algorithm (SA) and the independent checkpointing algorithm (ICA), is evaluated. The performance is based on a detailed implementation of algorithms published earlier in the C language. A benchmark that simulates a variety of application requirements and considers variations in the number of proc... View full abstract»

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  • Experiences with distributed query processing

    Publication Year: 1990, Page(s):192 - 199
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (945 KB)

    Different implementations of an experimental distributed query processing system which is constructed on top of existing database management systems (DBMSs) are presented. A performance evaluation is carried out. It is shown that the response times of query execution are affected significantly by the degree of site autonomy, interferences among processes, interface with the local DBMSs, and commun... View full abstract»

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  • Query processing for temporal databases

    Publication Year: 1990, Page(s):200 - 208
    Cited by:  Papers (14)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (656 KB)

    A stream processing approach for temporal query processing and optimization is discussed. Given properly sorted data, the implementation of temporal joins and semijoins as stream processors can be very effective. Also discussed are the tradeoffs among sort orders, the amount of local workspace, and multiple scans over input streams; in particular, the authors are interested in the effect of sort o... View full abstract»

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  • Parallelism in object-oriented query processing

    Publication Year: 1990, Page(s):209 - 217
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (880 KB)

    An investigation of parallel query processing issues in object-oriented databases is conducted. First the query model to be used is introduced. Three areas in which parallelism can be exploited in the query model are identified. The performance of each of the three areas is measured by mapping the query model to a parallel architecture and using analytic comparisons with the case in which query pr... View full abstract»

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  • Extending object-oriented concepts to support engineering applications

    Publication Year: 1990, Page(s):220 - 227
    Cited by:  Papers (6)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (731 KB)

    A presentation is made of a structure-function (S-F) paradigm for representing engineering designs. The S-F paradigm treats structures and functions as first-class objects by modeling the physical configuration of the design as structural objects and the behavior of the design as functional objects. The paradigm supports engineering designs by using the associative knowledge between structures and... View full abstract»

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  • Modeling design object relationships in PEGASUS

    Publication Year: 1990, Page(s):228 - 236
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (903 KB)

    A description is given of the preliminary data model design of a database system for CAD applications named Pegasus. The model is based on previously published work on extensible and object-oriented database systems. Novel ideas of the model that are presented include the use of relationship objects as a modeling construct to represent relationships of any degree, and replication and the reconcili... View full abstract»

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