Java網(wǎng)絡(luò)編程翻譯1.docx

Java網(wǎng)絡(luò)編程翻譯 姓名：常燦光 班級(jí)：2012163班 學(xué)號(hào)：201216323 專業(yè)：網(wǎng)絡(luò)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.當(dāng)你想到一個(gè)微型計(jì)算機(jī)的時(shí)候，或許你想到的只是設(shè)備本身。也就是，你認(rèn)為的視頻顯示器和鍵盤(pán)。還有更多這些設(shè)備。當(dāng)你想到一個(gè)微機(jī),也許你認(rèn)為是信息系統(tǒng)的一部分。一個(gè)信息系統(tǒng)有五個(gè)部分:人、程序、軟件、硬件和數(shù)據(jù)。People :It is easy to overlook people as oen of the five parts of a microcomputer system.人：在微型機(jī)五個(gè)部分當(dāng)中，很容易忽視人這一部分。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：在使用軟件,硬件和數(shù)據(jù)的時(shí)候，程序是規(guī)則或遵循的指導(dǎo)方針。通常,由計(jì)算機(jī)專家為特定組織編寫(xiě)的這些程序被記錄在冊(cè)。軟件和硬件制造商也提供與他們的產(chǎn)品手冊(cè)。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).軟件：軟件是另一個(gè)程序或程序組的名字。一個(gè)程序一步一步的指示,告訴計(jì)算機(jī)如何工作。軟件的目的是將數(shù)據(jù)(未處理的事件)轉(zhuǎn)化為信息(處理的事件)。Hardware:The hardware consists of the equipment:keyboard,monitor(video display screen),printer,the computer itself,and other devices.硬件：硬件包括這些設(shè)備：鍵盤(pán)，顯示器（視頻顯示屏幕），計(jì)算機(jī)本身，和其他設(shè)備。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.數(shù)據(jù)：數(shù)據(jù)由原始的、未經(jīng)處理的數(shù)據(jù)。原始數(shù)據(jù)的例子是你工作的和你付出效率的時(shí)間。通過(guò)計(jì)算機(jī)的處理后的數(shù)據(jù),它通常被稱為信息。這些信息的一個(gè)例子是欠你一個(gè)星期的工作工資報(bào)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.在大的計(jì)算機(jī)系統(tǒng)中，有專門(mén)的人員寫(xiě)程序，開(kāi)發(fā)軟件和捕捉數(shù)據(jù)。在微型計(jì)算機(jī)系統(tǒng)中，然而，終端用戶常常使用這些操作。在五大部件中，數(shù)據(jù)技能常常被認(rèn)為是最突出的問(wèn)題。Principal Features of Database數(shù)據(jù)庫(kù)的主要特點(diǎn)A description of the principal features of database manager software for microcomputers follows:微型數(shù)據(jù)庫(kù)管理軟件的主要特點(diǎn)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) 定位和顯示:所有數(shù)據(jù)庫(kù)程序的一個(gè)基本功能就是快速定位文件記錄的能力。在我們的示例中,程序搜索每一條記錄，為了在一個(gè)特殊區(qū)域去匹配你想要的數(shù)據(jù)。這就是所謂的查詢數(shù)據(jù)庫(kù)。記錄可以顯示在屏幕上用來(lái)查看、更新或編輯。例如,如果一個(gè)員工的行動(dòng),需要更改地址字段。記錄通過(guò)搜索數(shù)據(jù)庫(kù)中快速定位找到相匹配的員工記錄您所指定的名稱字段。一旦記錄顯示,地址字段可以改變。(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.分類:數(shù)據(jù)庫(kù)管理者很容易改變?cè)谝粋€(gè)文件中的順序。正常情況下,在記錄出現(xiàn)的順序中，記錄被輸入到數(shù)據(jù)庫(kù),如雇用一個(gè)人的日期。然而,這可能不是最好的方法。有許多方法可以快速重新排列文件中的記錄。例如,您可能想要打印出整個(gè)按照姓氏首字母順序排列的名單的員工。為了稅收的 目的，你可能需要按照社會(huì)安全號(hào)列出所有的員工。(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.計(jì)算和格式:許多數(shù)據(jù)庫(kù)程序包含內(nèi)置的數(shù)學(xué)公式。在辦公室,例如,您可以使用這個(gè)特性來(lái)找到最高或最低傭金收入?？梢杂?jì)算的平均傭金收入的銷售人員在一個(gè)國(guó)家的一部分。這些信息可以被組織為一個(gè)表和報(bào)告格式打印出來(lái)。Database Management System(DBMS)數(shù)據(jù)庫(kù)管理系統(tǒng)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.數(shù)據(jù)庫(kù)這個(gè)詞常常用來(lái)描述一組關(guān)聯(lián)的文件被組織成一個(gè)集成的、復(fù)雜的結(jié)構(gòu),提供了不同的人不同的訪問(wèn)相同的數(shù)據(jù)。例如,機(jī)動(dòng)車(chē)輛管理部門(mén)有一個(gè)數(shù)據(jù)庫(kù)的所有信息的文件(如,過(guò)去的犯罪記錄、信念等)可能向警察部門(mén)提供,其他信息(e.f超速罰單)可能提供許可部門(mén),還有其他信息(例如,數(shù)量和類型的信念)可能去保險(xiǎn)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.數(shù)據(jù)庫(kù)管理系統(tǒng)是一個(gè)非常復(fù)雜的軟件程序,控制組織,存儲(chǔ)和(字段、記錄和文件)的數(shù)據(jù)在數(shù)據(jù)庫(kù)中。它還控制數(shù)據(jù)庫(kù)的安全性和完整性。DBMS接受請(qǐng)求數(shù)據(jù)。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當(dāng)使用DBMS,信息系統(tǒng)可以更容易改變組織的信息需求的變化?？梢蕴砑有碌念悇e的數(shù)據(jù)到數(shù)據(jù)庫(kù)中(1) Data Security and Integrity數(shù)據(jù)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.數(shù)據(jù)安全防止不知名用戶查看或更新數(shù)據(jù)庫(kù)。使用密碼,用戶被允許訪問(wèn)整個(gè)數(shù)據(jù)庫(kù)或數(shù)據(jù)庫(kù)的子集,稱為子模式。例如,一個(gè)雇員數(shù)據(jù)庫(kù)可以包含所有關(guān)于個(gè)別員工的數(shù)據(jù),但是一群用戶只能授權(quán)查看工資數(shù)據(jù)。而另一些則只允許訪問(wèn)工作歷史和醫(yī)療數(shù)據(jù)。DBMS能夠保持?jǐn)?shù)據(jù)庫(kù)的完整性,不允許多個(gè)用戶同時(shí)更新相同的記錄。DBMS可以繼續(xù)重復(fù)記錄的數(shù)據(jù)庫(kù);例如,客戶沒(méi)有兩個(gè)相同的客戶數(shù)量(關(guān)鍵字段)可以進(jìn)入數(shù)據(jù)庫(kù)。(2) Interactive query相互查詢Query languages and report writters allow to interactively interrogate the database and analayze its data.查詢語(yǔ)言和報(bào)告允許交互式查詢數(shù)據(jù)庫(kù)和分析其數(shù)據(jù)。(3) Interactive data Entry and Updating交互式數(shù)據(jù)錄入和更新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提供了一種交互式地輸入和更新數(shù)據(jù)庫(kù),此功