數(shù)據(jù)庫(kù)管理外文資料及翻譯

1、<p>　　外文資料翻譯—原文部分</p><p>　　Database Management</p><p>　　(From http://wenku.baidu.com/view/51857f07cc17552707220879.html,2011)</p><p>　　Database (sometimes spelled database) is

2、also called an electronic database, referring to any collections of data, or information, that is specially organized for rapid search and retrieval by a computer. Databases are structured to facilitate the storage, retr

3、ieval modification and deletion of data in conjunction with various data-processing operations. Database can be stored on magnetic disk or tape, optical disk, or some other secondary storage device.</p><p>　

4、　A database consists of a file or a set of files. The information in the these files may be broken down into records, each of which consists of one or more fields are the basic units of data storage, and each field typic

5、ally contains information pertaining to one aspect or attribute of the entity described by the database. Using keywords and various sorting commands, users can rapidly search, rearrange, group, and select the fields in m

6、any records to retrieve or create reports on particular aggre</p><p>　　Database records and files must be organized to allow retrieval of the information. Early system were arranged sequentially (i.e., alpha

7、betically, numerically, or chronologically); the development of direct-access storage devices made possible random access to data via indexes. Queries are the main way users retrieve database information. Typically the u

8、ser provides a string of characters, and the computer searches the database for a corresponding sequence and provides the source materials in wh</p><p>　　In flat databases, records are organized according to

9、 a simple list of entities; many simple databases for personal computers are flat in structure. The records in hierarchical databases are organized in a treelike structure, with each level of records branching off into a

10、 set of smaller categories. Unlike hierarchical databases, which provide single links between sets of records at different levels, network databases create multiple linkages between sets by placing links, or pointers, to

11、 one se</p><p>　　The information in many databases consists of natural-language texts of documents; number-oriented database primarily contain information such as statistics, tables, financial data, and raw

12、scientific and technical data. Small databases can be maintained on personal-computer systems and may be used by individuals at home. These and larger databases have become increasingly important in business life. Typica

13、l commercial applications include airline reservations, production management, medical rec</p><p>　　DBMS Structuring Techniques</p><p>　　Sequential, direct, and other file processing approaches

14、are used to organize and structure data in single files. But a DBMS is able to integrate data elements from several files to answer specific user inquiries for information. That is, the DBMS is able to structure and tie

15、together the logically related data from several large files. </p><p>　　Logical Structures. Identifying these logical relationships is a job of the data administrator. A data definition language is used for

16、this purpose. The DBMS may then employ one of the following logical structuring techniques during storage access, and retrieval operations.</p><p>　　List structures. In this logical approach, records are lin

17、ked together by the use of pointers. A pointer is a data item in one record that identifies the storage location of another logically related record. Records in a customer master file, for example, will contain the name

18、and address of each customer, and each record in this file is identified by an account number. During an accounting period, a customer may buy a number of items on different days. Thus, the company may maintain an invoic

19、e </p><p>　　Hierarchical (tree) structures. In this logical approach, data units are structured in multiple levels that graphically resemble an “upside down” tree with the root at the top and the branches fo

20、rmed below. There’s a superior-subordinate relationship in a hierarchical (tree) structure. Below the single-root data component are subordinate elements or nodes, each of which, in turn, “own” one or more other elements

21、 (or none). Each element or branch in this structure below the root has only a single</p><p>　　Network Structures. Unlike the tree approach, which does not permit the connection of branches, the network stru

22、cture permits the connection of the nodes in a multidirectional manner. Thus, each node may have several owners and may, in turn, own any number of other data units. Data management software permits the extraction of the

23、 needed information from such a structure by beginning with any record in a file.</p><p>　　Relational structures. A relational structure is made up of many tables. The data are stored in the form of “relatio

24、ns” in these tables. For example, relation tables could be established to link a college course with the instructor of the course, and with the location of the class. To find the name of the instructor and the location o

25、f the English class, the course/instructor relation is searched to get the name (“Fitt”), and the course/location relation is a relatively new database structuring </p><p>　　Physical Structures. People visua

26、lize or structure data in logical ways for their own purposes. Thus, records R1 and R2 may always be logically linked and processed in sequence in one particular application. However, in a computer system it’s quite poss

27、ible that these records that are logically contiguous in one application are not physically stored together. Rather, the physical structure of the records in media and hardware may depend not only on the I/O and storage

28、devices and techniques used</p><p>　　Database Management Features of Oracle </p><p>　　Oracle includes many features that make the database easier to manage. We’ve divided the discussion in this

29、section into three categories: Oracle Enterprise Manager, add-on packs, backup and recovery.</p><p>　　Oracle Enterprise Manager</p><p>　　As part of every Database Server, Oracle provides the Ora

30、cle Enterprise Manager (EM), a database management tool framework with a graphical interface used to manage database users, instances, and features (such as replication) that can provide additional information about the

31、Oracle environment.</p><p>　　Prior to the Oracle8i database, the EM software had to be installed on Windows 95/98 or NT-based systems and each repository could be accessed by only a single database manager a

32、t a time. Now you can use EM from a browser or load it onto Windows 95/98/2000 or NT-based systems. Multiple database administrators can access the EM repository at the same time. In the EM repository for Oracle9i, the s

33、uper administrator can define services that should be displayed on other administrators’ consoles, and</p><p>　　Add-on packs</p><p>　　Several optional add-on packs are available for Oracle, as d

34、escribed in the following sections. In addition to these database-management packs, management packs are available for Oracle Applications and for SAP R/3.</p><p>　　standard Management Pack </p><p

35、>　　The Standard Management Pack for Oracle provides tools for the management of small Oracle databases (e.g., Oracle Server/Standard Edition). Features include support for performance monitoring of database contention

36、, I/O, load, memory use and instance metrics, session analysis, index tuning, and change investigation and tracking.</p><p>　　Diagnostics Pack </p><p>　　You can use the Diagnostic Pack to monito

37、r, diagnose, and maintain the health of Enterprise Edition databases, operating systems, and applications. With both historical and real-time analysis, you can automatically avoid problems before they occur. The pack als

38、o provides capacity planning features that help you plan and track future system-resource requirements. </p><p>　　Tuning Pack</p><p>　　With the Tuning Pack, you can optimise system performance b

39、y identifying and tuning Enterprise Edition databases and application bottlenecks such as inefficient SQL, poor data design, and the improper use of system resources. The pack can proactively discover tuning opportunitie

40、s and automatically generate the analysis and required changes to tune the systems. </p><p>　　Change Management Pack</p><p>　　The Change Management Pack helps eliminate errors and loss of data w

41、hen upgrading Enterprise Edition databases to support new applications. It impact and complex dependencies associated with application changes and automatically perform database upgrades. Users can initiate changes with

42、easy-to-use wizards that teach the systematic steps necessary to upgrade.</p><p>　　Availability</p><p>　　Oracle Enterprise Manager can be used for managing Oracle Standard Edition and/or Enterpr

43、ise Edition. Additional functionality is provided by separate Diagnostics, Tuning, and Change Management Packs.</p><p>　　Backup and Recovery</p><p>　　As every database administrator knows, backi

44、ng up a database is a rather mundane but necessary task. An improper backup makes recovery difficult, if not impossible. Unfortunately, people often realize the extreme importance of this everyday task only when it is to

45、o late –usually after losing business-critical data due to a failure of a related system.</p><p>　　The following sections describe some products and techniques for performing database backup operations.</

46、p><p>　　Recovery Manager</p><p>　　Typical backups include complete database backups (the most common type), database backups, control file backups, and recovery of the database. Previously, Oracle’

47、s Enterprise Backup Utility (EBU) provided a similar solution on some platforms. However, RMAN, with its Recovery Catalog stored in an Oracle database, provides a much more complete solution. RMAN can automatically locat

48、e, back up, restore, and recover databases, control files, and archived redo logs. RMAN for Oracle9i can restart back</p><p>　　Incremental backup and recovery</p><p>　　RMAN can perform increment

49、al backups of Enterprise Edition databases. Incremental backups back up only the blocks modified since the last backup of a datafile, tablespace, or database; thus, they’re smaller and faster than complete backups. RMAN

50、can also perform point-in-time recovery, which allows the recovery of data until just prior to a undesirable event.</p><p>　　Legato Storage Manager</p><p>　　Various media-management software ven

51、dors support RMAN. Oracle bundles Legato Storage Manager with Oracle to provide media-management services, including the tracking of tape volumes, for up to four devices. RMAN interfaces automatically with the media-mana

52、gement software to request the mounting of tapes as needed for backup and recovery operations.</p><p>　　Availability</p><p>　　While basic recovery facilities are available for both Oracle Standa

53、rd Edition and Enterprise Edition, incremental backups have typically been limited to Enterprise Edition.</p><p>　　Choosing between Oracle and SQL Server</p><p>　　I have to decide between using

54、the Oracle database and WebDB vs. Microsoft SQL Server with Visual Studio. This choice will guide our future Web projects. What are the strong points of each of these combinations and what are the negatives?</p>&

55、lt;p>　　Lori: Making your decision will depend on what you already have. For instance, if you want to implement a Web-based database application and you are a Windows-only shop, SQL Server and the Visual Studio package

56、 would be fine. But the Oracle solution would be better with mixed platforms.</p><p>　　There are other things to consider, such as what extras you get and what skills are required. WebDB is a content managem

57、ent and development tool that can be used by content creators, database administrators, and developers without any programming experience. WebDB is a browser-based tool that helps ease content creation and provides monit

58、oring and maintenance tools. This is a good solution for organizations already using Oracle. Oracle also scales better than SQL Server, but you will need to hav</p><p>　　The SQL Sever/Visual Studio approach

59、is more difficult to use and requires an experienced object-oriented programmer or some extensive training. However, you do get a fistful of development tools with Visual Studio: Visual Basic, Visual C++, and Visual Inte

60、rDev for only $1,619. Plus, you will have to add the cost of the SQL Server, which will run you $1,999 for 10 clients or $3,999 for 25 clients-a less expensive solution than Oracle’s.</p><p>　　Oracle also ha

61、s a package solution that starts at $6,767, depending on the platform selected. The Oracle.com suite includes not only WebDB and Oracle8i but also other tools for development such as the Oracle application server, JDevel

62、oper, and Workplace Templates, and the suite runs on more platforms than the Microsoft solution does. This can be a good solution if you are a start-up or a small to midsize business. Buying these tools in a package is l

63、ess costly than purchasing them individually.</p><p>　　Much depends on your skill level, hardware resources, and budget. I hope this helps in your decision-making.</p><p>　　Brooks: I totally agr

64、ee that this decision depends in large part on what infrastructure and expertise you already have. If the decision is close, you need to figure out who’s going to be doing the work and what your priorities are.</p>

65、<p>　　These two products have different approaches, and they reflect the different personalities of the two vendors. In general, Oracle products are designed for very professional development efforts by top-notch

66、programmers and project leaders. The learning period is fairly long, and the solution is pricey; but if you stick it out you will ultimately have greater scalability and greater reliability.</p><p>　　If your

67、 project has tight deadlines and you don’t have the time and/or money to hire a team of very expensive, very experienced developers, you may find that the Oracle solution is an easy way to get yourself in trouble. There’

68、s nothing worse than a poorly developed Oracle application.</p><p>　　What Microsoft offers is a solution that’s aimed at rapid development and low-cost implementation. The tools are cheaper, the servers you’

69、ll run it on are cheaper, and the developers you need will be cheaper. Choosing SQL Sever and Visual Studio is an excellent way to start fast.</p><p>　　Of course, there are trade-offs. The key problem I have

70、 with Visual Studio and SQL Server is that you’ll be tied to Microsoft operating systems and Intel hardware. If the day comes when you need to support hundreds of thousands of users, you really don’t have anywhere to go

71、other than buying hundreds of servers, which is a management nightmare.</p><p>　　If you go with the Microsoft approach, it sounds like you may not need more than Visual Interdev. If you already know that you

72、’re going to be developing ActiveX components in Visual Basic or Visual C++, that’s warning sign that maybe you should look at the Oracle solution more closely.</p><p>　　I want to emphasize that, although th

73、ese platforms have their relative strengths and weaknesses, if you do it right you can build a world-class application on either one. So if you have an organizational bias toward one of the vendors, by all means go with

74、it. If you’re starting out from scratch, you’re going to have to ask yourself whether your organization leans more toward perfectionism or pragmatism, and realize that both “isms” have their faults.</p><p>　

75、　外文資料翻譯—譯文部分</p><p><b>　　數(shù)據(jù)庫(kù)管理</b></p><p>　　(引自http://wenku.baidu.com/view/51857f07cc17552707220879.html,2011)</p><p>　　數(shù)據(jù)庫(kù)(有時(shí)拼數(shù)據(jù)庫(kù))也被稱(chēng)為電子數(shù)據(jù)庫(kù),指任何的數(shù)據(jù)或信息集合,它是特別為由計(jì)算機(jī)進(jìn)行的快速搜索

76、和檢索所組織的。在結(jié)合各種數(shù)據(jù)處理操作時(shí)數(shù)據(jù)庫(kù)有組織的便于存儲(chǔ)、檢索修改、刪除數(shù)據(jù)。數(shù)據(jù)庫(kù)能被存儲(chǔ)在磁盤(pán)或磁帶、光盤(pán),或其他一些輔助存儲(chǔ)設(shè)備。</p><p>　　一個(gè)數(shù)據(jù)庫(kù)由一個(gè)或一組文件組成。這些文件中的信息可分解成一個(gè)個(gè)記錄,每一種都有一個(gè)或多個(gè)域,它是數(shù)據(jù)存儲(chǔ)的基本單位,每個(gè)域一般含有有關(guān)被數(shù)據(jù)庫(kù)描述的實(shí)體的一個(gè)方面或?qū)傩缘男畔?。通過(guò)使用鍵盤(pán)和各種排序命令,用戶(hù)可以在許多記錄中快速查找、重排、分組和選擇相

77、應(yīng)的域檢索或創(chuàng)建特定集上的報(bào)表。</p><p>　　數(shù)據(jù)庫(kù)記錄和文件必須組織成允許信息的檢索。早期的系統(tǒng)順序安排(例如,按字母順序,按時(shí)間順序數(shù)值,或按年代地);隨機(jī)方向存儲(chǔ)設(shè)備的發(fā)展使通過(guò)索引隨機(jī)存取數(shù)據(jù)成為可能。用戶(hù)檢索數(shù)據(jù)庫(kù)信息的主要途徑是查詢(xún)。典型地,用戶(hù)提供一字符串,而計(jì)算機(jī)搜索數(shù)據(jù)庫(kù)對(duì)應(yīng)的序列和提供那些字符出現(xiàn)地方的原始資源。用戶(hù)可以要求,舉例來(lái)說(shuō),在域的內(nèi)容上一個(gè)人的姓是史密斯的所有的記錄。許多大

78、型數(shù)據(jù)庫(kù)的用戶(hù)必須能夠在任何特定時(shí)間迅速地操縱其內(nèi)部的信息。此外,大企業(yè)和其他組織傾向于建立包含許多獨(dú)立的相關(guān)文件、甚至重疊的數(shù)據(jù),在他們的數(shù)據(jù)之間,處理活動(dòng)往往需要從幾個(gè)文件和他們的數(shù)據(jù)要求數(shù)據(jù)連接。幾種不同類(lèi)型的數(shù)據(jù)庫(kù)管理系統(tǒng)已經(jīng)發(fā)展成支持這些要求:平面的、分層的、網(wǎng)狀的、有關(guān)系的、面向?qū)ο蟮摹?lt;/p><p>　　在平面的數(shù)據(jù)庫(kù)中，記錄根據(jù)簡(jiǎn)單的實(shí)體列表被組織;為個(gè)人電腦設(shè)計(jì)的簡(jiǎn)單數(shù)據(jù)庫(kù)大多呈平面結(jié)構(gòu)。在層

79、次數(shù)據(jù)庫(kù)中記錄被組織成樹(shù)狀結(jié)構(gòu),在每層記錄上分叉成一系列更小的類(lèi)別。與分層的數(shù)據(jù)庫(kù)不同,在不同層次上報(bào)告間提供單鏈聯(lián)系的網(wǎng)絡(luò)數(shù)據(jù)庫(kù)通過(guò)放置鏈接或者指針創(chuàng)建集合間多重聯(lián)系使一套記錄聯(lián)系另一套;網(wǎng)絡(luò)數(shù)據(jù)庫(kù)的速度和功能性導(dǎo)致了商業(yè)上的廣泛應(yīng)用。關(guān)系數(shù)據(jù)庫(kù)應(yīng)用于不能被連接表達(dá)的文件或記錄的關(guān)聯(lián);一個(gè)簡(jiǎn)單的平面列表變成一張表或“關(guān)系”,多重聯(lián)系能算數(shù)地關(guān)聯(lián)成域所需要的信息。面向?qū)ο蟮臄?shù)據(jù)庫(kù)存儲(chǔ)和操作更復(fù)雜的被稱(chēng)為“對(duì)象”的數(shù)據(jù)結(jié)構(gòu),它能被組織成可

80、以從較高束縛類(lèi)繼承性質(zhì)的層次類(lèi);該數(shù)據(jù)庫(kù)結(jié)構(gòu)是最為靈活和適應(yīng)性強(qiáng)的。</p><p>　　許多數(shù)據(jù)庫(kù)中的信息包含自然語(yǔ)言文本的文件;以數(shù)字為方向的數(shù)據(jù)庫(kù)主要包含如統(tǒng)計(jì)、表格、財(cái)務(wù)數(shù)據(jù)及原始科學(xué)和技術(shù)數(shù)據(jù)的信息。小數(shù)據(jù)庫(kù)可以被個(gè)人計(jì)算機(jī)系統(tǒng)所維護(hù),也可以用于個(gè)人家庭。這些小的和較大的數(shù)據(jù)庫(kù)在商業(yè)事務(wù)中變得越來(lái)越重要。典型的商業(yè)應(yīng)用包括飛機(jī)票預(yù)定、生產(chǎn)管理、醫(yī)院醫(yī)療記錄、保險(xiǎn)公司法律記錄。最大的數(shù)據(jù)庫(kù)通常是由政府機(jī)構(gòu)

81、、商業(yè)組織和大學(xué)維持。這些數(shù)據(jù)庫(kù)可以包含如種類(lèi)繁多的目錄的材料的文本。參考數(shù)據(jù)庫(kù)包含著作為圖書(shū)、期刊、和其他已發(fā)表的文獻(xiàn)中信息的指南的參考文獻(xiàn)或索引。成千上萬(wàn)的這種公開(kāi)的數(shù)據(jù)庫(kù)已經(jīng)存在,涵蓋包括從法律、醫(yī)藥、工程到新聞和時(shí)事,比賽,分類(lèi)廣告,教學(xué)課程的內(nèi)容。例如科學(xué)家、醫(yī)生、律師、金融分析師、證券經(jīng)紀(jì)人和所有類(lèi)型的研究人員的專(zhuān)業(yè)人士日益依賴(lài)于這些數(shù)據(jù)庫(kù)進(jìn)行迅速、選擇性訪(fǎng)問(wèn)大量的信息。</p><p>　　DBMS

82、（數(shù)據(jù)庫(kù)管理系統(tǒng)）構(gòu)建技術(shù)</p><p>　　序列,直接和其他文件處理方法是用來(lái)依次組織和結(jié)構(gòu)數(shù)據(jù)文件。但DBMS能夠從幾個(gè)文件整合數(shù)據(jù)要素以回應(yīng)特定的信息使用訪(fǎng)問(wèn)。即DBMS能夠組織和捆綁來(lái)自幾個(gè)大的檔案的在邏輯上相關(guān)的數(shù)據(jù)。</p><p>　　邏輯結(jié)構(gòu)。識(shí)別這些邏輯關(guān)系是一個(gè)數(shù)據(jù)管理員的工作。數(shù)據(jù)定義語(yǔ)言是用于此目的。數(shù)據(jù)庫(kù)系統(tǒng)可以在儲(chǔ)存訪(fǎng)問(wèn)和檢索操作期間使用下列邏輯構(gòu)建技術(shù)。&l

83、t;/p><p>　　鏈表結(jié)構(gòu)。在這種邏輯方法中,記錄通過(guò)使用的指針被連在一起。指針是一種在記錄中識(shí)別另一個(gè)邏輯上相關(guān)記錄存儲(chǔ)位置的數(shù)據(jù)項(xiàng)。一個(gè)客戶(hù)主文件的記錄,將包含如每一位客戶(hù)的姓名及地址,在該文件中每一個(gè)記錄通過(guò)一個(gè)帳號(hào)鑒定。在一個(gè)會(huì)計(jì)期間,客戶(hù)可以在不同的日子購(gòu)買(mǎi)若干物品。因此,公司可以維持一個(gè)發(fā)票文件以反映這些交易。一個(gè)鏈表結(jié)構(gòu)可以在在任何特定時(shí)間顯示未付的發(fā)票的這種情況下使用。每條在顧客發(fā)票文件上的記錄。

84、這條發(fā)票記錄,將會(huì)輪流被連接到后來(lái)發(fā)票的客戶(hù)。在鏈上最后的發(fā)票將通過(guò)使用如指針的特殊字符來(lái)鑒定</p><p>　　層次(樹(shù))結(jié)構(gòu)。在這個(gè)邏輯方法中,數(shù)據(jù)單位在多個(gè)層次結(jié)構(gòu)中被組織,像一個(gè)圖形化”上下顛倒的“根在上和分支在下的樹(shù)。有一個(gè)上下級(jí)層次(樹(shù))結(jié)構(gòu)的關(guān)系。 在表示根的數(shù)據(jù)組件下面是從屬的元素或節(jié)點(diǎn),反過(guò)來(lái),每個(gè)節(jié)點(diǎn)“擁有”一個(gè)或多個(gè)其他元素(或無(wú))。在這個(gè)結(jié)構(gòu)上的每個(gè)元素或分支根下面只有一個(gè)單獨(dú)的物主。因

85、此,一個(gè)客戶(hù)擁有一個(gè)發(fā)票、發(fā)票擁有下屬的項(xiàng)目。在一個(gè)樹(shù)形結(jié)構(gòu)中分支是沒(méi)有關(guān)系的。</p><p>　　網(wǎng)狀結(jié)構(gòu)。不像不允許分支的連接的樹(shù)方法,網(wǎng)狀結(jié)構(gòu)允許節(jié)點(diǎn)多方向的連接。因此,每個(gè)節(jié)點(diǎn)可能會(huì)包含許多所有者和,反過(guò)來(lái),可能擁有任何數(shù)量的其它數(shù)據(jù)單位。數(shù)據(jù)管理軟件允許來(lái)自通過(guò)文件中任何記錄開(kāi)始的結(jié)構(gòu)的所需信息的提取。</p><p>　　關(guān)系結(jié)構(gòu)。關(guān)系結(jié)構(gòu)是由許多的表組成。這些數(shù)據(jù)是儲(chǔ)存在這

86、些表的“關(guān)系”中。例如,關(guān)系表能建立大學(xué)課程與課程講師與班的位置的聯(lián)系。為了找出這個(gè)講師的名字和英語(yǔ)課的位置,課程/講師的關(guān)系搜索得到(“Fitt”)的名字,該課程/位置的關(guān)系是一種相對(duì)較新的有望在未來(lái)廣泛實(shí)施的數(shù)據(jù)庫(kù)構(gòu)建方法。</p><p>　　物理結(jié)構(gòu)。人們?yōu)榱诉_(dá)到他們自己的目的通過(guò)數(shù)據(jù)合邏輯的方法想象或構(gòu)造數(shù)據(jù)。因此,記錄R1和R2邏輯上串聯(lián),通過(guò)特定的應(yīng)用按順序處理。然而,在一個(gè)計(jì)算機(jī)系統(tǒng)中，很可能這些

87、記錄在一個(gè)應(yīng)用程序邏輯相鄰物理上但不被保存在一起。更確切的說(shuō),媒體記錄的物理結(jié)構(gòu)和硬件可能不僅取決于I/O和存儲(chǔ)設(shè)備和技術(shù)的應(yīng)用,而且取決于用戶(hù)分配給的從R1和 R2中發(fā)現(xiàn)的數(shù)據(jù)的不同的邏輯關(guān)系。例如,R1和R2可記錄每2個(gè)星期發(fā)貨給在同一城市同一區(qū)域的賒戶(hù)。從航運(yùn)部門(mén)經(jīng)理的觀點(diǎn)來(lái)看,然后,R1和R2在根據(jù)地域組織的航運(yùn)報(bào)告是連續(xù)的記錄。但在A/R應(yīng)用中,由R1、R2代表的客戶(hù)可以根據(jù)他們的帳號(hào)是截然分開(kāi)的從而被認(rèn)定他們的帳戶(hù)被處理。簡(jiǎn)

88、而言之,那么,在許多基于計(jì)算機(jī)的信息系統(tǒng)中存儲(chǔ)記錄的物理位置對(duì)用戶(hù)來(lái)說(shuō)是無(wú)形的。</p><p>　　Oracle數(shù)據(jù)庫(kù)管理特點(diǎn)</p><p>　　Oracle有許多使數(shù)據(jù)庫(kù)易于管理的特點(diǎn)。我們將這部分討論分為三類(lèi):Oracle企業(yè)管理器,附加包,備份和恢復(fù)。</p><p>　　Oracle企業(yè)管理器</p><p>　　作為每個(gè)數(shù)據(jù)庫(kù)服

89、務(wù)器的一部分,Oracle提供Oracle 企業(yè)管理器(EM)、數(shù)據(jù)庫(kù)管理工具的圖形界面框架,用于管理數(shù)據(jù)庫(kù)用戶(hù),實(shí)例,及特征(如復(fù)制),可以提供有關(guān)Oracle環(huán)境額外的信息環(huán)境。</p><p>　　在Oracle8i數(shù)據(jù)庫(kù)之前,EM軟件需要安裝Windows 95/98或基于NT系統(tǒng),每個(gè)庫(kù)只能一次通過(guò)單一的數(shù)據(jù)庫(kù)管理器被存取。現(xiàn)在你可以從一個(gè)瀏覽器或加載它到Windows95/98/2000或基于NT的系

90、統(tǒng)來(lái)使用EM。多個(gè)數(shù)據(jù)庫(kù)管理員可以在同一時(shí)間內(nèi)訪(fǎng)問(wèn)EM庫(kù)。在Oracle9i的EM庫(kù)中,超級(jí)管理員可以定義會(huì)顯示在其他管理員控制臺(tái)上,管理區(qū)域可以被建立起來(lái)的服務(wù)。</p><p><b>　　附加包</b></p><p>　　Oracle可使用如隨后的章節(jié)描述的多個(gè)可選的附加包。除了這些數(shù)據(jù)庫(kù)管理包,管理包還供應(yīng) Oracle應(yīng)用和SAP R/3。</p&g

91、t;<p><b>　　(一)標(biāo)準(zhǔn)管理包</b></p><p>　　Oracle標(biāo)準(zhǔn)管理包提供了小型Oracle數(shù)據(jù)庫(kù)管理工具(例如,Oracle服務(wù)器/標(biāo)準(zhǔn)版)。功能包括對(duì)數(shù)據(jù)庫(kù)競(jìng)爭(zhēng)的性能監(jiān)控、I/O、加載、內(nèi)存使用和實(shí)例度量、會(huì)話(huà)分析、指標(biāo)調(diào)整、改變調(diào)查和跟蹤的支持。</p><p><b>　　(二)診斷包</b></

92、p><p>　　你可以用診斷包監(jiān)測(cè)、診斷、和維持企業(yè)版數(shù)據(jù)庫(kù)、操作系統(tǒng)和應(yīng)用程序的健康。既有歷史和實(shí)時(shí)分析,你就可以在發(fā)生前自動(dòng)避免問(wèn)題。診斷包也提供能力計(jì)劃的功能,幫助你計(jì)劃并跟蹤未來(lái)系統(tǒng)資源的要求。</p><p><b>　　(三)性能優(yōu)化包</b></p><p>　　有了性能優(yōu)化包,您可以來(lái)通過(guò)鑒定和改制企業(yè)版數(shù)據(jù)庫(kù)和如低效的SQL,數(shù)據(jù)

93、質(zhì)量不佳的設(shè)計(jì)及不當(dāng)使用系統(tǒng)資源的應(yīng)用的瓶頸優(yōu)化系統(tǒng)性能。性能優(yōu)化包可以提前發(fā)現(xiàn)優(yōu)化機(jī)遇,自動(dòng)生成分析和必需的變更來(lái)調(diào)整系統(tǒng)。</p><p><b>　　(四)變更管理包</b></p><p>　　變更管理包在升級(jí)企業(yè)版數(shù)據(jù)庫(kù)來(lái)支持新的應(yīng)用時(shí)有助于消除錯(cuò)誤和數(shù)據(jù)丟失。它影響和復(fù)雜的依賴(lài)性的變化和應(yīng)用程序變化相關(guān),自動(dòng)完成數(shù)據(jù)庫(kù)升級(jí)。用戶(hù)可以通過(guò)教授系統(tǒng)升級(jí)必要步驟

94、的易于使用的向?qū)?lái)引發(fā)變更。</p><p><b>　　(五)可用性</b></p><p>　　Oracle企業(yè)管理器可以被用于管理Oracle標(biāo)準(zhǔn)版和/或企業(yè)版。通過(guò)獨(dú)立的診斷、調(diào)整及變更管理包提供額外的功能。</p><p><b>　　備份和恢復(fù)</b></p><p>　　每一個(gè)數(shù)據(jù)庫(kù)管

95、理員知道,備份數(shù)據(jù)庫(kù)是一個(gè)相當(dāng)普通但必要的任務(wù)。不適當(dāng)?shù)膫浞菔够謴?fù)困難,甚至是不可能的。不幸的是,人們只有當(dāng)它已經(jīng)太遲了-通常在由于相關(guān)系統(tǒng)錯(cuò)誤失去了商業(yè)決定性的數(shù)據(jù)后才意識(shí)到這種日常任務(wù)的極端重要性。</p><p>　　接下來(lái)的章節(jié)將描述一些產(chǎn)品和技術(shù)來(lái)進(jìn)行數(shù)據(jù)庫(kù)備份操作。</p><p><b>　　1)恢復(fù)管理器</b></p><p>

96、;　　典型的備份包括了完整的數(shù)據(jù)庫(kù)備份(最常見(jiàn)的類(lèi)型),數(shù)據(jù)庫(kù)備份、控制文件備份、數(shù)據(jù)庫(kù)恢復(fù)。以前,Oracle企業(yè)備份工具(EBU)在某些平臺(tái)提供了一個(gè)類(lèi)似的解決方案。然而,RMAN以其存儲(chǔ)在一個(gè)Oracle目錄中的恢復(fù)目錄,提供了一個(gè)更完整的解決方案。RMAN能自動(dòng)定位,備份,還原和恢復(fù)數(shù)據(jù)庫(kù),控制文件和歸檔日志。Oracle9i RMAN可以當(dāng)備份終止時(shí)重新開(kāi)始備份和恢復(fù)及實(shí)施恢復(fù)窗體政策政策。Oracle企業(yè)管理器備份管理器提供

97、了一個(gè)基于GUI RMAN界面。</p><p><b>　　2)增量備份和恢復(fù)</b></p><p>　　RMAN可以執(zhí)行增量企業(yè)版數(shù)據(jù)庫(kù)的備份。增量備份備份的只是自從上次數(shù)據(jù)文件,表空間或數(shù)據(jù)庫(kù)的備份的修改部分;因此,他們要比完整的備份更小、更快。RMAN也可以執(zhí)行時(shí)間點(diǎn)恢復(fù),允許數(shù)據(jù)恢復(fù)到不良事件發(fā)生前。</p><p>　　3)Leg

98、ato存儲(chǔ)管理器</p><p>　　各種中間管理軟件供應(yīng)商支持RMAN。 Oracle束及對(duì)Oracle Legato存儲(chǔ)管理器提供中間管理服務(wù),包括磁帶卷跟蹤,及多達(dá)四臺(tái)設(shè)備。RMAN與中間管理軟件自動(dòng)聯(lián)系來(lái)要求安裝所需的磁帶備份和恢復(fù)操作。</p><p><b>　　4)可用性</b></p><p>　　雖然基本恢復(fù)的設(shè)施標(biāo)準(zhǔn)版和企業(yè)

99、版Oracle都能使用,但增量備份通常局限于企業(yè)版。</p><p>　　Oracle和SQL服務(wù)器之間的抉擇</p><p>　　“我要決定是使用Oracle數(shù)據(jù)庫(kù)及WebDB還是SQL Server與Visual Studio。這個(gè)選擇將引導(dǎo)我們的未來(lái)的網(wǎng)絡(luò)項(xiàng)目。每一個(gè)這樣的組合的長(zhǎng)處是什么了,并且短處是什么?</p><p>　　羅莉:決定將取決于你已經(jīng)擁有的