2,365 research outputs found

    Programming constructs for database system implementation in EXODUS

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    User Defined Types and Nested Tables in Object Relational Databases

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    Bernadette Byrne, Mary Garvey, ‘User Defined Types and Nested Tables in Object Relational Databases’, paper presented at the United Kingdom Academy for Information Systems 2006: Putting Theory into Practice, Cheltenham, UK, 5-7 June, 2006.There has been much research and work into incorporating objects into databases with a number of object databases being developed in the 1980s and 1990s. During the 1990s the concept of object relational databases became popular, with object extensions to the relational model. As a result, several relational databases have added such extensions. There has been little in the way of formal evaluation of object relational extensions to commercial database systems. In this work an airline flight logging system, a real-world database application, was taken and a database developed using a regular relational database and again using object relational extensions, allowing the evaluation of the relational extensions.Peer reviewe

    The Cord Approach to Extensible Concurrency Control

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    Database management systems (DBMSs) have been increasingly used for advanced application domains, such as software development environments, workflow management systems, computer-aided design and manufacturing, and managed healthcare. In these domains, the standard correctness model of serializability is often too restrictive. The authors introduce the notion of a concurrency control language (CCL) that allows a database application designer to specify concurrency control policies to tailor the behavior of a transaction manager. A well-crafted set of policies defines an extended transaction model. The necessary semantic information required by the CCL run-time engine is extracted from a task manager, a (logical) module by definition included in all advanced applications. This module stores task models that encode the semantic information about the transactions submitted to the DBMS. They have designed a rule-based CCL, called CORD, and have implemented a run-time engine that can be hooked to a conventional transaction manager to implement the sophisticated concurrency control required by advanced database applications. They present an architecture for systems based on CORD and describe how they integrated the CORD engine with the Exodus Storage Manager to implement altruistic locking

    Concurrent rule execution in active databases

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    Cataloged from PDF version of article.An active DBMS is expected to support concurrent as well as sequential rule execution in an efficient manner. Nested transaction model is a suitable tool to implement rule execution as it can handle nested rule firing and concurrent rule execution well. In this paper, we describe a concurrent rule execution model based on parallel nested transactions. We discuss implementation details of how the flat transaction model of OpenOODB has been extended by using Solaris threads in order to SUppOrt COnCUrrent eXeCUtiOU of rUkS.

    Language constructs for managing change in process-centered environments

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    Change is pervasive during software development, af-fecting objects, processes, and environments. In pro-cess centered environments, change management can be facilitated by software-process programming, which for-malizes the representation of software products and pro-cesses using software-process programming languages (SPPLs). To fully realize this goal SPPLs should in-clude constructs that specifically address the problems of change management. These problems include lack of representation of inter-object relationships, weak se-mantics for inter-object relationships, visibility of im-plementations, lack of formal representation of soft-ware processes, and reliance on programmers to manage change manually

    Modules as values in a persistent object store

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    Journal ArticleWe report on an object manager (OM) providing persistent implementations for C ++ classes. Our OM generalizes this problem to that of managing persistent modules, where the module concept is an abstract data type (ADT). This approach permits a powerful suite of module manipulation operations to be applied uniformly to modules of many provenances, including non-class based entities such as conventional object files, application libraries, and shared system libraries. OMOS, a generalized linker and loader, plays a central role in our OM. Class implementations are represented by OMOS modules, which in turn are constructed from OMOS meta-objects encapsulating linkage blueprints. We cleanly solve the problems of (i) logically (but not physically) including executable object files in our OM, (ii) reconciling class inheritance history and linkage history, and (iii) supporting alternative implementations of a class, for client interoperability or version control
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