DB2性能优化主要方法

IBM公司的关系数据库管理系统产品可以运行在许多不同的操作系统之上,包括MVS,VM,VSE,OS/400,OS/2,AIX,HP—UX,Solaris,Win—dowsNT,Macintosh等等。所有这些产品都称为DATA BASE2,合称为DB2家族。DB2作为一个大型数据库系统,对许多不同的资源如CPU、内存、磁盘、网络等都有复杂的调配和使用。在动态环境下     

如何编写和调用DB2的存储过程

DB2是IBM公司的数据库系统高性能产品,该产品可以运行在许多不同的操作系统之上,形成DB2产品家族,提供全功能的关系数据库管理。存储过程(stored procedure)是安装和执行在服务器上的一段程序,但它可以被客户机上的应用程序调用。存储过程本身也可以用SQL语句。利用存储过程可将应用程序中多次与数据库交换的相同逻辑操作集中到服务器上执行,从而减少客户机与服务器之间的网络数据交换次数,提高应用效率,减少运行时间。     

一种移植Sybase用户数据库的简便方法

滁洲人行原服务器上安装了Unix 系统、Sybase 数据库和出口收汇核销系统。该系统自从1997年投入运行以来,其出口收汇核销用户数据库经历了数十次修改,有三十多个补丁程序,现在已很难整理出创建该用户数据库的完整脚本程序。为此,在替换服务器时,需要对原服务器上Sybase Master 数据库有关系统表进行分析,确立为创建出口收汇核销用户数据库所需要的物理存储参数和用户参数,通过使用简单的命令语句将该数据库移植到     

通过Windows任务计划程序实现DB2数据的自动备份

随着信息化进程的加快，许多企事业单位的数据库系统发挥着越来越重要的作用。在这种情况下，大量的信息数据成为日常运作的核心决策依据，一旦数据库服务器遭受破坏，就会给单位带来巨大的损失。因此，如何防止数据的意外丢失和破坏，保证数据的安全已成为迫切需要研究的重要课题。     

整理Sybase数据库的碎片

Sybase数据库在我国金融系统中应用十分广泛。由于其应用程序每天对数据库进行大量的插入更新、删除等操作，在数据库的物理存储介质上产生了大量存储碎片，从而影响了存储的效率以及数据库应用运行的速度。下面笔者将简要介绍一种Sybase数据库碎片的整理方法。     

主机DB2数据库重组技术的应用与实践

生产数据库系统的维护管理工作是确保生产系统性能和数据可用性的一项重要的工作。主机DB2数据库系统是中国工商银行（以下简称＂工行＂）业务系统的核心,而DB2数据库重组工作是数据库日常维护管理工作的重点。本文通过探讨主机DB2数据库重组技术在工行的应用与实践,     

巧手架鹊桥,滔滔银河等闲渡--PowerBuilder连接 Sybase数据库的应用技巧

PowerBuilder(PB)是一种跨平台的且功能强大、性能优异的开发工具。在客户端／服务器(C／S)系统结构的应用模式中，作为客户端的一种面向对象的可视化设计工具，在与数据库相连接操作的系统中得到广泛的应用。笔利用PB开发外汇管理局“非贸易外汇业务管理系统”时，将PB应用程序移植到Sybase数据库的应用过程中，     

利用DB2 DJRA实现数据库复制

一、引言人力资源管理系统虽不是实时性系统,但人员流动及人员基本情况(如年龄、职务、职称和工作部门等)经常变化,为及时有效掌握人力资源情况,下级行须定时向上级行上报和更新数据,保持不同数据库间数据的同步。由于我行人力资源管理系统采用DB2数据库,因此,可以考虑用EXPORT和IMPORT命令方式导出、导入数据,但不利于业务人员使用和维护;采用DB2MOVE可以在不同系统之间复制数据,但无法复制外键等约束以及视图、触发器等;也可考虑采用编程方式进行不同数据库之间数据同步。在实践过程中,笔者发现用DB2数据库的DJRA可以较好地实…     

DB2数据库的查询优化

DB2是一种高性能的数据库管理系统,应用程序的执行最终归结为数据库中 SQL 语句的执行,而查询操作在各种数据库操作中所占据的比重最大,查询的优劣在很大程度上反映了一个数据库性能的优劣,SQL 语句的执行效率最终决定了数据库的性能。因此,设计高效合理的 SQL 语句,提高 SQL 语句的质量,这对数据库性能的提高非常重要。在DB2数据库管理系统中,应用程序的每个查询语句     

由Informix到Sybase的数据迁移方法

一、引言 建设银行山东省分行于2002年9月在全省范围内启用了新一代业务处理系统,从而实现了全省建行业务数据由物理集中到逻辑集中的过渡.数据集中到省分行后,有关数据库数据的维护职能也随之上移省分行.由于在省分行数据库的定期数据清理中,有些逻辑集中前的历史数据已难以查询,因此作为二级分行来说,有必要根据数据逻辑集中时利用Informix实用程序dbexport卸载下来的数据库数据重建数据库,以备营业网点查询之需.     

Florida's Pension Election: From DB to DC and Back

During the year 2002, the State of Florida's 600,000 public employees were given the choice of converting their traditional defined benefit (DB) pension plan into an individual‐account defined contribution (DC) plan with full control over asset allocation and investment decisions. To mitigate some of the risk and uncertainty in the decision, the State granted each employee electing the DC plan an additional option to switch back (i.e., change their mind once) at any point prior to retirement. This option has been labeled the 2nd election by the State and the cost of reentry is fixed at the accumulated benefit obligation of their pension entitlement, which is the present value of the life annuity. Our article presents some original analytic insights relating to the optimal time and financial value of this unique 2nd election. Although our model is deterministic in nature, we believe that it provides a number of intuitive insights that are quite robust. Our results can be contrasted with Lachance, Mitchell, and Smetters (2003) . We estimate that the increase in retirement wealth that arises from having the 2nd election is equivalent to at most 30 percent in future value, and only when utilized optimally. Furthermore, for most State employees above the age of 45, the 2nd election has little economic value because the DB plan dominates the DC plan from day one. Of course, it remains to be seen what percent of Florida's 600,000 employees will elect to behave rationally with their newfound pension autonomy.     

浅谈OS/390下DB2数据库的备份和恢复

OS/390作为IBM的主机操作系统,在中国主要应用于金融、制造、民航等领域,而在这些领域,信息、数据的重要性不言而喻,作为IBM最主要的数据库管理软件DB2,在数据的安全性方面提供了比较完备的备份和恢复机制.     

Estimation of cost efficiencies from mergers: application to US radio

This article estimates fixed‐cost efficiencies from mergers using a dynamic oligopoly model in which mergers and repositioning of products are endogenous. The inference is based on revealed preference approach selecting cost synergies that rationalize observed merger decisions. The estimates can be used to assess the total welfare impact of retrospective and counterfactual mergers. The framework is applied to estimate cost efficiencies after the 1996 deregulation of U.S. radio industry. Within the period of 1996 to 2006 the cost savings resulting from mergers amount to $1.2 billion per year (equally split across economies of scale and within‐format cost synergies).     

Recovering copulas from limited information and an application to asset allocation

This paper proposes an entropy-based method to construct a new class of copulas - the most entropic canonical copulas (MECC). Our empirical study focuses on an investment problem for an investor with a constant relative risk aversion (CRRA) utility function allocating wealth between the Dow Jones Large-Cap and Small-Cap indices, of which the contemporaneous dependence can be modeled by the MECC or other commonly-used copulas. Both the theoretical analysis of the method and the empirical study indicate the potential for enormous statistical and economic gains as a result of using the MECC.     

An application of a three-factor performance index to measure stockholder gains from merger

This article re-examines the magnitude of stockholder gains from merger. To measure stockholder gains we employ four alternative two-factor market-industry models in combination with a matched non-merging control group. The four two-factor models are based on either the capital asset pricing model or Black's (1972) zero-beta model combined with two alternative industry factors. The four models are shown to produce generally consistent results. However, the results from a two-factor model are sometimes different from the results of a simpler one-factor model. Also, the introduction of a third factor, the non-merging control group, is shown to have a substantial impact on performance measurement.     

The application of artificial intelligence to medicine

This article reviews current developments in artificial intelligence as they apply to medicine. Initial applications of this approach to medicine are being actively pursued in medical diagnosis, interpretation of data from chemical studies, and the development of computer models of human behavioural processes. Of special interest is a new research programme established at Stanford University called SUMEX, one of whose major goals is the application of artificial intelligence to medicine. Within the framework of SUMEX, research is actively under way in a number of aspects of biomedical research and clinical medicine. Some of the work reviewed includes the DENDRAL and META-DENDRAL programs, the Protein Crystallography System, SECS, MYCIN, DIALOG, CASNET, the Present Illness Program, PARRY, and Believer. Suggestions for future applications of artificial intelligence to medicine will include clinical patient-record information systems, pharmacology, prosthetics, gerontology, and radiology.     

L-performance with an application to hedge funds

This paper introduces a new parametric fund performance measure, called the L-performance. The L-performance is an alternative to the Sharpe performance, which is commonly used in practice despite its inability to account for skewness and heavy tails of unconditional return distributions. The L-performance improves upon the Sharpe measure in this respect. Technically, it resembles the Sharpe measure in that it is defined as a ratio of the first- and second-order moments, which are the trimmed L-moments instead of the conventional (power) moments. The trimming parameters allow for focusing the L-performance on specific risk levels of interest, according to financial risk criteria. For illustration, a set of L-performances is computed for a variety of hedge funds. The empirical study shows the use of L-performance for fund ranking and return smoothing (manipulation) control.