【正文】 用數(shù)據(jù)類(lèi)型的圖表，它給出實(shí)體。附錄3外文資料譯文Database system The conception sued for describing files and databases has varied substantially in the same organization. A database may be defined as a collection of interrelated data stored together with as little redundancy as possible to serve one or more applications in an optimal fashion。模式和子模式是由數(shù)據(jù)庫(kù)管理系統(tǒng)使用的，數(shù)據(jù)庫(kù)管理系統(tǒng)的主要作用是執(zhí)行數(shù)據(jù)操作時(shí)服務(wù)于應(yīng)用程序。數(shù)據(jù)獨(dú)立這個(gè)術(shù)語(yǔ)經(jīng)常提出作為一個(gè)數(shù)據(jù)主要屬性之一，它是指數(shù)據(jù)和使用數(shù)據(jù)的應(yīng)用程序相互獨(dú)立，目的改變一項(xiàng)時(shí)不用改變另一項(xiàng)，當(dāng)一個(gè)單一的數(shù)據(jù)相集合服務(wù)于不同的應(yīng)用時(shí)，不同的應(yīng)用程序感知數(shù)據(jù)項(xiàng)與記錄之間的管理說(shuō)明有聯(lián)系，也和數(shù)據(jù)是怎樣存貯的和存在那里有關(guān)，用于許多應(yīng)用中的在數(shù)據(jù)之間有很多種內(nèi)在的聯(lián)系。主關(guān)鍵字定義為能唯一的確定一個(gè)記錄或一個(gè)元組的關(guān)鍵字。數(shù)據(jù)模型在用戶(hù)截面上排出了存貯結(jié)構(gòu)和存取策略的細(xì)節(jié)，模型提供了一種高層次的數(shù)據(jù)關(guān)系，然而為了正確的使用關(guān)系數(shù)據(jù)模型，關(guān)系的設(shè)計(jì)必須是完備的和正確的。層次型數(shù)據(jù)模型是基于數(shù)型結(jié)構(gòu)的，由結(jié)點(diǎn)和數(shù)值組成，一個(gè)結(jié)點(diǎn)是描述此點(diǎn)上實(shí)體屬性的數(shù)據(jù)集合。主關(guān)鍵字是很重要的。大多數(shù)數(shù)據(jù)庫(kù)的最主要特點(diǎn)之一是他們需要不斷的更新和增加。我們必須區(qū)別一個(gè)記錄和一個(gè)記錄的事例，當(dāng)談?wù)摰饺w人員的記錄時(shí)它是一個(gè)真正的記錄類(lèi)型，而不是與它相結(jié)合的數(shù)據(jù)值。 a mon and controlled approach is used in adding new data and in modifying and retrieving existing data within the data base one system is said to contain a collection of databases if they are entirely separate in structure.At abase may be designed for batch processing, realtimes processing, or inline processing. a data base system involves application program, DBMS and database.One o he most important characteristic of most databases is that they will constantly need to change and grow easy restructuring of the database must be possible as new data types and new applications are added.The restructuring should be possible without having to rewrite the application program and in general should cause as little upheaval as possible the ease with which a database can be changed will have a major effect on the rate at which dataprocessing application can be developed in a corporation.The term data independence is often quoted as being one of the main attributes of a database int implies th