Java网络编程翻译1.docx

Java网络编程翻译 姓名：常灿光 班级：2012163班 学号：201216323 专业：网络工程Database and Database ManagementWhen you think of a microcomputer,perhaps you think of just the equipment itself.That is,you think of the video display screen or the keyboard.There is more to it than that.The way to think about a microcomputer is as part of an information system.An information system have five parts :people,procedures,software,hardware,and data.当你想到一个微型计算机的时候，或许你想到的只是设备本身。也就是，你认为的视频显示器和键盘。还有更多这些设备。当你想到一个微机,也许你认为是信息系统的一部分。一个信息系统有五个部分:人、程序、软件、硬件和数据。People :It is easy to overlook people as oen of the five parts of a microcomputer system.人：在微型机五个部分当中，很容易忽视人这一部分。Procedures:Procedures are rules or guidelines to follow when using software,hardware,and data.Typically,these Procedures are documented in manuals written by computer specialists for particular orgization.Software and hardware manufacturers also provide manuals with their products.程序：在使用软件,硬件和数据的时候，程序是规则或遵循的指导方针。通常,由计算机专家为特定组织编写的这些程序被记录在册。软件和硬件制造商也提供与他们的产品手册。Software:Software is another name for a program or programs.A program is the step-by-step instructions that tell the computer how to do its work.The purpose of software is to convert data(unprocessed facts)into information(processed facts).软件：软件是另一个程序或程序组的名字。一个程序一步一步的指示,告诉计算机如何工作。软件的目的是将数据(未处理的事件)转化为信息(处理的事件)。Hardware:The hardware consists of the equipment:keyboard,monitor(video display screen),printer,the computer itself,and other devices.硬件：硬件包括这些设备：键盘，显示器（视频显示屏幕），计算机本身，和其他设备。Data:Data consists of the raw,unprocessed facts.Examples of raw facts are hours you worked and you pay rate.After the data is processed through the computer,it is usually called information.An example of such information is the total wages owed you for a weeks work.数据：数据由原始的、未经处理的数据。原始数据的例子是你工作的和你付出效率的时间。通过计算机的处理后的数据,它通常被称为信息。这些信息的一个例子是欠你一个星期的工作工资报酬。In large computer systems,there are specialist who deal with writing procedures,developing software,and capturing data.In mictocomputer systems,however,end users often perform these operations.Among the five parts,data skills often considered the most outstanding concern.在大的计算机系统中，有专门的人员写程序，开发软件和捕捉数据。在微型计算机系统中，然而，终端用户常常使用这些操作。在五大部件中，数据技能常常被认为是最突出的问题。Principal Features of Database数据库的主要特点A description of the principal features of database manager software for microcomputers follows:微型数据库管理软件的主要特点如下：(1) Locate and Display:A basic feature of all database programs is the capability to locate records in the file quickly.In our example,the program searches each record for a match in a particular field to whatever data you specify.This is called querying a database.The records can then be displayed on the screen for viewing,updating,or editing.For example,if an employee moves,the address field needs to be changed.The record is quickly located by searching the database to find the employee record that matches the name field you specify.Once the record is displayed,the address field can be changed.(1) 定位和显示:所有数据库程序的一个基本功能就是快速定位文件记录的能力。在我们的示例中,程序搜索每一条记录，为了在一个特殊区域去匹配你想要的数据。这就是所谓的查询数据库。记录可以显示在屏幕上用来查看、更新或编辑。例如,如果一个员工的行动,需要更改地址字段。记录通过搜索数据库中快速定位找到相匹配的员工记录您所指定的名称字段。一旦记录显示,地址字段可以改变。(2) Sort:Database managers make it easy to change the order of recoreds in a file.Normally,records are entered into the database in the order they occur,such as the date a person is hired.This may not be the best way,however.There are a number of ways you can quickly rearrange the records in the file.For example,you might want to print out an entire alphabetical list of employees by last name.For tax purposes,you might want to list employees by social security number.分类:数据库管理者很容易改变在一个文件中的顺序。正常情况下,在记录出现的顺序中，记录被输入到数据库,如雇用一个人的日期。然而,这可能不是最好的方法。有许多方法可以快速重新排列文件中的记录。例如,您可能想要打印出整个按照姓氏首字母顺序排列的名单的员工。为了税收的 目的，你可能需要按照社会安全号列出所有的员工。(3) Calculate and Format:Many database programs contain built-in math formulas.In the office,for example,you can use this feature to find the highest or lowest commissions earned.You can calculate the average of the commissions earned by the sales force in one part of the country.This information can be organized as a table and printed out in a report format.计算和格式:许多数据库程序包含内置的数学公式。在办公室,例如,您可以使用这个特性来找到最高或最低佣金收入。可以计算的平均佣金收入的销售人员在一个国家的一部分。这些信息可以被组织为一个表和报告格式打印出来。Database Management System(DBMS)数据库管理系统The term database is often used to describe a collection of ralated files that is organized into an integrated,sophisticated structure that provides different people varied access to the same data.For example,the Department of MOtor Vehicles has a database of all the information in the file(e.g.,a past criminal record,convictions,and the like)may be made available to police departments,other information(e.f.,a balance due on a speeding ticket)may be made available to licensing bureaus,and still other information(e.g.,number and type of convictions)may go to insurance companies.数据库这个词常常用来描述一组关联的文件被组织成一个集成的、复杂的结构,提供了不同的人不同的访问相同的数据。例如,机动车辆管理部门有一个数据库的所有信息的文件(如,过去的犯罪记录、信念等)可能向警察部门提供,其他信息(e.f超速罚单)可能提供许可部门,还有其他信息(例如,数量和类型的信念)可能去保险公司。A database management system is an extremely complex set of software programs that control the organization,storage and retieval of data(fields,records and files)in a database.It also controls the security and integrity of the database.The DBMS accepts requests for data.数据库管理系统是一个非常复杂的软件程序,控制组织,存储和(字段、记录和文件)的数据在数据库中。它还控制数据库的安全性和完整性。DBMS接受请求数据。When a DBMS is used,information systems can be changed much more easily as the organizations information requirements change.New categories of data can be added to the database当使用DBMS,信息系统可以更容易改变组织的信息需求的变化。可以添加新的类别的数据到数据库中(1) Data Security and Integrity数据安全性和完整性Data security prevents unathorized users from viewing or updating the database.Using passwards,user are allowed access to the entire database or subsets of the database,called subschemas.For example,an employee database can contain all the data about an individual employee,but one group of users may be authorized to view only payroll data.while others are allowed access to only work history and medical data.The DBMS can maintain the integrity of the database by not allowing more than one user to update the same record at the same time.The DBMS can keep duplicate records out of the database;for example,no two customers with the same customer numbers(key field)can be entered into the database.数据安全防止不知名用户查看或更新数据库。使用密码,用户被允许访问整个数据库或数据库的子集,称为子模式。例如,一个雇员数据库可以包含所有关于个别员工的数据,但是一群用户只能授权查看工资数据。而另一些则只允许访问工作历史和医疗数据。DBMS能够保持数据库的完整性,不允许多个用户同时更新相同的记录。DBMS可以继续重复记录的数据库;例如,客户没有两个相同的客户数量(关键字段)可以进入数据库。(2) Interactive query相互查询Query languages and report writters allow to interactively interrogate the database and analayze its data.查询语言和报告允许交互式查询数据库和分析其数据。(3) Interactive data Entry and Updating交互式数据录入和更新If the DBMS provides a way to interactively enter and update the database,as wellas interrogate it,this capability allows for managing personal databases.However,it does not automatically leave an audit trail of actions and does not provide the kinds of controls necessary in a multi-user organization.These controls are only available when a set of application programs is customized for each data entry and updating function.This is one of the most common misconceptions about sophisticated business systems that are used in personal compucters.Thouroughly comprehensive and sophisticated business systems can be developed in dBase,Paradox,FoxPro and other DBMS;however,they are creat by experienced prograrmmers using the DBMSs own programming language.That is not the same as users who creat and manage personal files that are not part of the mainstream company system.如果DBMS提供了一种交互式地输入和更新数据库,此功