167,687 research outputs found

    The Mirror MMDBMS architecture

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    Handling large collections of digitized multimedia data, usually referred to as multimedia digital libraries, is a major challenge for information technology. The Mirror DBMS is a research database system that is developed to better understand the kind of data management that is required in the context of multimedia digital libraries (see also URL http://www.cs.utwente.nl/~arjen/mmdb.html). Its main features are an integrated approach to both content management and (traditional) structured data management, and the implementation of an extensible object-oriented logical data model on a binary relational physical data model. The focus of this work is aimed at design for scalability

    A physical store for a relational database in the STL style

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    We introduce an object-oriented design of a physical store system for a relational database. The design and implementation of the physical store are in the style of C++ standard template library. They stress separation of memory allocation, iterators, container types, and the types of data in the store. The physical store system is part of the Know-It-All database project, under way at Concordia University. The contents of the physical store system are described using SQL data definition language. The main tasks of the physical store system are the bulk-loading of data, the support for the bulk creation of indexes, and data retrieval. The design hides the use of the secondary store. The problems with the existing physical stores are a lack of type checking and type safety. Our design and implementation draw upon advanced uses of C++ templates, as typified by the standard template library, type lists, the tuple library from boost.org, and dynamic loading. Furthermore we reuse design patterns, the mySQL parser, and the POST++ persistent object store

    A physical store for a relational database in the STL style

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    We introduce an object-oriented design of a physical store system for a relational database. The design and implementation of the physical store are in the style of C++ standard template library. They stress separation of memory allocation, iterators, container types, and the types of data in the store. The physical store system is part of the Know-It-All database project, under way at Concordia University. The contents of the physical store system are described using SQL data definition language. The main tasks of the physical store system are the bulk-loading of data, the support for the bulk creation of indexes, and data retrieval. The design hides the use of the secondary store. The problems with the existing physical stores are a lack of type checking and type safety. Our design and implementation draw upon advanced uses of C++ templates, as typified by the standard template library, type lists, the tuple library from boost.org, and dynamic loading. Furthermore we reuse design patterns, the mySQL parser, and the POST++ persistent object store

    A framework for object-relational mapping with an example in C++

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    As the Object-Oriented programming technique becomes more and more popular in contemporary software design, issues related to persistent objects must be addressed. This thesis introduces a framework for Object-Relational Mapping. The framework is intended to simplify the handling of persistent objects in a Relational Database System. The framework's architecture consists of two layers: an object layer that contains the infrastructure for persistent objects and a storage layer that provides an interface to the Physical Storage System. As contributions, I have introduced my original work including mapping inheritance with inheritance, a particular solution for aggregation and associations mapping, a cache of object references for constructing objects and name conventions for preserving object maps. The Framework for Object-Relational Mapping is a C++ Framework (a set of Classes). It supports most of relational database systems. Developers can use these classes to obtain abilities about object relational mapping. In this thesis, a teaching assignment planner project is used to test my framework's performance in saving coding work

    A generalized system performance model for object-oriented database applications

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    Although relational database systems have met many needs in traditional business applications, such technology is inadequate for non-traditional applications such as computer-aided design, computer-aided software engineering, and knowledge bases. Object-oriented database systems (OODB) enhance the data modeling power and performance of database management systems for these applications. Response time is an important issue facing OODB. However, standard measures of on-line transaction processing are irrelevant for OODB . Benchmarks compare alternative implementations of OODB system software, running a constant application workload. Few attempts have been made to characterize performance implications of OODB application design, given a fixed OODB and operating system platform. In this study, design features of the 007 Benchmark database application (Carey, DeWitt, and Naughton, 1993 ) were varied to explore the impact on response time to perform database operations Sensitivity to the degree of aggregation and to the degree of inheritance in the application were measured. Variability in response times also was measured, using a sequence of database operations to simulate a user transaction workload. Degree of aggregation was defined as the number of relationship objects processed during a database operation. Response time was linear with the degree of aggregation. The size of the database segment processed, compared to the size of available memory, affected the coefficients of the regression line. Degree of inheritance was defined as the Number of Children (Chidamber and Kemerer, 1994) in the application class definitions, and as the extent to which run-time polymorphism was implemented. In this study, increased inheritance caused a statistically significant increase in response time for the 007 Traversal 1 only, although this difference was not meaningful. In the simulated transaction workload of nine 007 operations, response times were highly variable. Response times per operation depended on the number of objects processed and the effect of preceding operations on memory contents. Operations that used disparate physical segments or had large working sets relative to the size of memory caused large increases in response time. Average response times and variability were reduced by removing these operations from the sequence (equivalent to scheduling these transactions at some time when the impact would be minimized)

    Two Case Studies of Subsystem Design for General-Purpose CSCW Software Architectures

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    This paper discusses subsystem design guidelines for the software architecture of general-purpose computer supported cooperative work systems, i.e., systems that are designed to be applicable in various application areas requiring explicit collaboration support. In our opinion, guidelines for subsystem level design are rarely given most guidelines currently given apply to the programming language level. We extract guidelines from a case study of the redesign and extension of an advanced commercial workflow management system and place them into the context of existing software engineering research. The guidelines are then validated against the design decisions made in the construction of a widely used web-based groupware system. Our approach is based on the well-known distinction between essential (logical) and physical architectures. We show how essential architecture design can be based on a direct mapping of abstract functional concepts as found in general-purpose systems to modules in the essential architecture. The essential architecture is next mapped to a physical architecture by applying software clustering and replication to achieve the required distribution and performance characteristics
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