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用C++实现OODB中对象多版本 总被引:1,自引:0,他引:1
作者利用Sybase作底层的数据存储,在C++中扩展了永久类,实现了OODB的一个重要功能,文中讨论的是在此基础上,利用C++语言重载能力,和关系数据库便于集合操作的特性,扩展我版本类,实现OODB对象多版本。 相似文献
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需求工程知识库/PL——RKB/PL(requirement—engineeringknowledgebase/PL)是保持C++原有风格对C++进行的持久性扩充.为支持对象的持久性,RKB/PL在C++对象类的基础上扩充了以约束声明加强对象状态的用户监控;引入簇来表达对象类的集合含义;引入集合、簇、簇闭包的遍历机制来支持对象查询.为支持这些语言机制,RKB/PL具有一个由一组build—in对象类层次、类型信息库及接口函数、系统状态表以及系统服务函数等构成的运行时系统.本文讨论了RKB/PL中这些机制的表示、相应的运行时系统的组成以及它们的主要实现技术.RKB/PL已成功地用于实现“软件需求获取助手FRA”系统的需求工程知识库子系统. 相似文献
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对象持久化技术是一种数据存储方法,其目的是为了使程序开发者更加方便的访问数据.对象持久化技术解决了面向对象技术和关系数据库技术的不匹配问题,使得程序员从数据库细节中解放出来,让程序员有更多的精力去处理事务逻辑. 相似文献
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通过实例介绍了利用Hibernate实现对象持久化的过程,并对持久化过程中对象创建的时序和状态进行了分析。采用Hibernate进行持久化有利于提高开发的灵活性,有利于提高数据访问效率。 相似文献
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Hibernate是一个对象持久化工具,它通过其强大的O/R映射功能将Java对象同存放于关系数据库中的数据进行映射,避免了开发人员使用大量的SQL语句通过JDBC的方式对数据库进行操作,可以有效地提高开发的效率. 相似文献
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本文提出持久对象访问的自动捕捉技术,该技术是面向对象数据库系统在保持对象级的并发控制、版本管理和约束检查的条件下,实现持久对象与易变对象访问方式的一致性,进而实现面向对象数据库与程序设计语言的无缝结合的关键技术. 相似文献
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POTENTIAL is a virtual database machine based on general computing platforms,especially parllel computing platforms.It provides a complete solution to high-performance database systems by a ‘virtual processor virtual data bus virtual memory‘ architecture.Virtual processors manage all CPU resources in the system,on which various operations are running.Virtual data bus is responsible for the management of data transmission between associated operations.which forms the higes of the entire system.Virtual memory provides efficient data storage and buffering mechanisms that conform to data reference behaviors in database systems.The architecture of POTENTIAL is very clear and has many good features,including high efficiency,high scalability,high extensibility,high portability,etc. 相似文献
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多媒体智能数据库系统MIDS(MultimediaIntelligentDatabaseSystem)的存储系统是一个强大的,高性能的对象存储系统,该存储系统是MIDS引擎的核心,它是基于虚存映身的存储系统,在Client/Server的体系结构下,为数据库提供了大容量,复杂的,共享的,多革体数据存取,然而又不失面的对象数据模型的种种优点,在本文中,我们将介绍基于虚存映射的对象存储系统的基本原理以 相似文献
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DMM:A dynamic memory mapping model for virtual machines 总被引:2,自引:0,他引:2
CHEN HaoGang WANG XiaoLin WANG ZhenLin ZHANG BinBin LUO YingWei & LI XiaoMing 《中国科学:信息科学(英文版)》2010,(6):1097-1108
Memory virtualization is an important part in the design of virtual machine monitors(VMM).In this paper,we proposed dynamic memory mapping(DMM) model,a mechanism that allows the VMM to change the mapping between a virtual machine's physical memory and the underlying hardware resource while the virtual machine is running.By utilizing DMM,the VMM can implement many novel memory management policies,such as Demand Paging,Swapping,Ballooning,Memory Sharing and Copy-On-Write,while preserving compatibility with va... 相似文献
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虚拟环境中物体物理特性的表示与处理 总被引:11,自引:0,他引:11
文中阐述了表示与处理虚拟物体和物理特性对虚拟环境逼真性重要意义,介绍了其研究内容,综述了当前的一些主要方法和关键技术,分析了目前存在的问题,并讨论了虚拟物体物理特性表示与处理的应用,最后展望了该研究领域的发展趋势。 相似文献
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EuLisp has an integrated object system with reflective capabilities. We discuss some example applications which use these facilities to experiment with some advanced and powerful concepts, namely, finalization, virtual shared memory and persistence. A secondary goal is to attempt to illustrate the additional possibilities of metaobject programming over non-metalevel techniques. 相似文献
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Recent explosive growth in physical memory configurations inverts the problem faced by traditional operating systems, which were built around the assumption of limited physical memory and plentiful virtual memory. With the introduction of the Pentium Pro, there is an aberration in the historical trend towards increased virtual space. Such processors have 36‐bit physical and 32‐bit logical addressing; with traditional algorithms, the smaller virtual space limits the number of concurrent processes as well as the total physical memory usable by an application. To address these problems, two general principles can be applied to any operating system to reduce its virtual memory needs: first, multiplexing different physical addresses over the same virtual—as opposed to multiplexing different virtual over the same physical, where the optimization was to share the physical memory across multiple processes; second, optimize virtual consumption by kernel pagepool data, by organizing data structures to extend their physical memory reach using the same amount of virtual space. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献