數(shù)據(jù)庫和c語言外文翻譯

1、<p><b>　　英文原文1：</b></p><p>　　《Professional C# Third Edition》 Simon Robinson, Christian Nagel, Jay Glynn, Morgan Skinner, Karli Watson, Bill Evjen. Wiley Publishing, Inc. 2006</p><

2、p>　　Where C# Fits In</p><p>　　In one sense, C# can be seen as being the same thing to programming languages as .NET is to the Windows environment. Just as Microsoft has been adding more and more features

3、to Windows and the Windows API over the past decade, Visual Basic and C++ have undergone expansion. Although Visual Basic and C++ have ended up as hugely powerful languages as a result of this, both languages also suffer

4、 from problems due to the legacies of how they have evolved.</p><p>　　In the case of Visual Basic 6 and earlier, the main strength of the language was the fact that it was simple to understand and didn’t mak

5、e many programming tasks easy, largely hiding the details of the Windows API and the COM component infrastructure from the developer. The downside to this was that Visual Basic was never truly object-oriented, so that la

6、rge applications quickly become disorganized and hard to maintain. As well as this, because Visual Basic’s syntax was inherited from early vers</p><p>　　C++, on the other hand, has its roots in the ANSI C++

7、language definition. It isn’t completely ANSI compliant for the simple reason that Microsoft first wrote its C++ compiler before the ANSI definition had become official, but it comes close. Unfortunately, this has led to

8、 two problems. First, ANSI C++ has its roots in a decade-old state of technology, and this shows up in a lack of support for modern concepts (such as Unicode strings and generating XML documentation), and in some archaic

9、 synta</p><p>　　The result is that on Windows, the language has become a complete mess. Just ask C++ developers how many definitions for a string they can think of: char*, LPTSTR, string, CString (MFC versio

10、n), CString (WTL version), wchar_t*, OLECHAR*, and so on.</p><p>　　Now enter .NET—a completely new environment that is going to involve new extensions to both languages. Microsoft has gotten around this by a

11、dding yet more Microsoft-specific keywords to C++, and by completely revamping Visual Basic into Visual Basic .NET, a language that retains some of the basic VB syntax but that is so different in design that we can consi

12、der it to be, for all practical purposes, a new language. It’s in this context that Microsoft has decided to give developers an alternative—</p><p>　　? Full support for classes and object-oriented programmin

13、g, including both interface and implementation inheritance, virtual functions, and operator overloading.</p><p>　　? A consistent and well-defined set of basic types.</p><p>　　? Built-in support

14、for automatic generation of XML documentation.</p><p>　　? Automatic cleanup of dynamically allocated memory.</p><p>　　? The facility to mark classes or methods with user-defined attributes. This

15、 can be useful for documentation and can have some effects on compilation (for example, marking methods to be compiled only in debug builds).</p><p>　　? Full access to the .NET base class library, as well as

16、 easy access to the Windows API (if you really need it, which won’t be all that often).</p><p>　　? Pointers and direct memory access are available if required, but the language has been designed in such a wa

17、y that you can work without them in almost all cases.</p><p>　　? Support for properties and events in the style of Visual Basic.</p><p>　　? Just by changing the compiler options, you can compile

18、 either to an executable or to a library of .NET components that can be called up by other code in the same way as ActiveX controls (COM components).</p><p>　　? C# can be used to write ASP.NET dynamic Web pa

19、ges and XMLWeb services.</p><p>　　Most of the above statements, it should be pointed out, do also apply to Visual Basic .NET and Managed C++. The fact that C# is designed from the start to work with .NET, ho

20、wever, means that its support for the features of .NET is both more complete, and offered within the context of a more suitable syntax than for those other languages. While the C# language itself is very similar to Java,

21、 there are some improvements: in particular, Java is not designed to work with the .NET environment.</p><p>　　Before we leave the subject, we should point out a couple of limitations of C#. The one area the

22、language is not designed for is time-critical or extremely high performance code—the kind where you really are worried about whether a loop takes 1,000 or 1,050 machine cycles to run through, and you need to clean up you

23、r resources the millisecond they are no longer needed. C++ is likely to continue to reign supreme among low-level languages in this area. C# lacks certain key facilities needed for ex</p><p><b>　　中文譯文：

24、</b></p><p><b>　　《C#的優(yōu)點(diǎn)》</b></p><p>　　C#在某種程度上可以看作是.NET面向Windows環(huán)境的一種編程語言。在過去的十幾年里，Microsoft給Windows和 Windows API添加了許多功能，VB和C++也經(jīng)歷了許多變化。雖然VB和C++最終已成為非常強(qiáng)大的語言，但這兩種語言也存在問題，因?yàn)樗鼈儽Ａ袅?/p>

25、原來的一些內(nèi)容。</p><p>　　對于Visual Basic來說，它的主要優(yōu)點(diǎn)是很容易理解，許多編程工作都很容易完成，基本上隱藏了Windows API和COM組件結(jié)構(gòu)的內(nèi)涵。其缺點(diǎn)是Visual Basic從來沒有實(shí)現(xiàn)真正意義上的面向?qū)ο螅源笮蛻?yīng)用程序很難分解和維護(hù)。另外，因?yàn)閂B的語法繼承于BASIC的早期版本(BASIC主要是為了讓初學(xué)者更容易理解，而不是為了編寫大型商業(yè)應(yīng)用程序)，所以不能真正成

26、為結(jié)構(gòu)化或面向?qū)ο蟮木幊陶Z言。</p><p>　　另一方面，C++在ANSI C++語言定義中有其自己的根。它與ANSI不完全兼容，因?yàn)镸icrosoft是在ANSI定義標(biāo)準(zhǔn)化之前編寫C++編譯器的，但已經(jīng)相當(dāng)接近了。遺憾的是，這導(dǎo)致了兩個(gè)問題。其一，ANSI C++是在十幾年前的技術(shù)條件下開發(fā)的，因此不支持現(xiàn)在的概念(例如Unicode字符串和生成XML文檔)，某些古老的語法結(jié)構(gòu)是為以前的編譯器設(shè)計(jì)的(例如成

27、員函數(shù)的聲明和定義是分開的)。其二，Microsoft同時(shí)還試圖把C++演變?yōu)橐环N用于在Windows上執(zhí)行高性能任務(wù)的語言—— 在語言中避免添加大量Microsoft專用的關(guān)鍵字和各種庫。其結(jié)果是在Windows中，該語言成為了一種非常雜亂的語言。讓一個(gè)C++開發(fā)人員說說字符串有多少個(gè)定義方式就可以說明這一點(diǎn)：char*、LPTSTR、string、CString (MFC 版本)、CString (WTL 版本)、wchar_t*和

28、 OLECHAR*等。</p><p>　　現(xiàn)在進(jìn)入.NET時(shí)代—— 一種全新的環(huán)境，它對這兩種語言都進(jìn)行了新的擴(kuò)展。Microsoft給C++添加了許多Microsoft專用的關(guān)鍵字，并把VB演變?yōu)閂B.NET，保留了一些基本的VB語法，但在設(shè)計(jì)上完全不同，從實(shí)際應(yīng)用的角度來看，VB.NET是一種新語言。在這里，Microsoft決定給開發(fā)人員另一個(gè)選擇—— 專門用于.NET、具有新起點(diǎn)的語言， 即Visual

29、 C# .NET。Microsoft在正式場合把C#描述為一種簡單、現(xiàn)代、面向?qū)ο?、類型非常安全、派生于C和C++的編程語言。大多數(shù)獨(dú)立的評論員對其說法是“派生于C、 C++ 和Java”。這種描述在技術(shù)上是非常準(zhǔn)確的，但沒有涉及到該語言的真正優(yōu)點(diǎn)。從語法上看，C#非常類似于C++和Java，許多關(guān)鍵字都是相同的，C#也使用類似于C++和Java的塊結(jié)構(gòu)，并用括號(｛｝)來標(biāo)記代碼塊，用分號分隔各行語句。對C#代碼的第一印象是它非常類似

30、于C++或Java代碼。但在這些表面上的類似性后面，C#學(xué)習(xí)起來要比C++容易得多，但比Java難一些。其設(shè)計(jì)與現(xiàn)代開發(fā)工具的適應(yīng)性要比其他語言更高，它同時(shí)具有Visual Basic的易</p><p>　　完全支持類和面向?qū)ο缶幊?，包括接口和繼承、虛函數(shù)和運(yùn)算符重載的處理。</p><p>　　定義完整、一致的基本類型集。</p><p>　　對自動(dòng)生成XML文

31、檔說明的內(nèi)置支持。</p><p>　　自動(dòng)清理動(dòng)態(tài)分配的內(nèi)存。</p><p>　　可以用用戶定義的特性來標(biāo)記類或方法。這可以用于文檔說明，對編譯有一定的影響(例如，把方法標(biāo)記為只在調(diào)試時(shí)編譯)。</p><p>　　對.NET基類庫的完全訪問權(quán)，并易于訪問Windows API。</p><p>　　可以使用指針和直接內(nèi)存訪問，但C#語言

32、可以在沒有它們的條件下訪問內(nèi)存。</p><p>　　以VB的風(fēng)格支持屬性和事件。</p><p>　　改變編譯器選項(xiàng)，可以把程序編譯為可執(zhí)行文件或.NET組件庫，該組件庫可以用與ActiveX控件(COM組件)相同的方式由其他代碼調(diào)用。</p><p>　　C#可以用于編寫ASP.NET動(dòng)態(tài)Web頁面和XML Web服務(wù)。</p><p>

33、　　應(yīng)該指出，對于上述大多數(shù)特性，VB.NET和Managed C++也具備。但C#從一開始就使用.NET，對.NET特性的支持不僅是完整的，而且提供了比其他語言更合適的語法。C#語言本身非常類似于Java，但其中有一些改進(jìn)，因?yàn)镴ava并不是為應(yīng)用于.NET環(huán)境而設(shè)計(jì)的。</p><p>　　在結(jié)束這個(gè)主題前，還要指出C#的兩個(gè)局限性。其一是該語言不適用于編寫時(shí)間急迫或性能非常高的代碼，例如一個(gè)要運(yùn)行1000或

34、1050次的循環(huán)，并在不需要這些循環(huán)時(shí)，立即清理它們所占用的資源。在這方面，C++可能仍是所有低級語言中的佼佼者。其二是C#缺乏性能極高的應(yīng)用程序所需要的關(guān)鍵功能，包括保證在代碼的特定地方運(yùn)行的內(nèi)聯(lián)函數(shù)和析構(gòu)函數(shù)。但這類應(yīng)用程序非常少。</p><p><b>　　英文原文2：</b></p><p>　　《DBA Survivor：Become a Rock Sta

35、r DBA》 by Thomas LaRock , Published By Apress . 2010</p><p>　　You know that a database is a collection of logically related data elements that may be structured in various ways to meet the multiple processin

36、g and retrieval needs of organizations and individuals. There’ s nothing new about databases—early ones were chiseled in stone, penned on scrolls, and written on index cards. But now databases are commonly recorded on ma

37、gnetizable media, and computer programs are required to perform the necessary storage and retrieval operations.</p><p>　　You’ll see in the following pages that complex data relationships and linkages may be

38、found in all but the simplest databases. The system software package that handles the difficult tasks associated with creating, accessing, and maintaining database records is called a database management system（DBMS）.The

39、 programs in a DBMS package establish an interface between the database itself and the users of the database.（These users may be applications programmers,　managers and others with information ne</p><p>　　If

40、the DBMS provides a way to interactively and update the database, as well as interrogate it capability allows for managing personal data-Aces however, it does not automatically leave an audit trail of actions and does no

41、t provide the kinds of control a necessary in a multiuser organization. These-controls are only available when a set of application programs are customized for each data entry and updating function.    　　

42、Software for personal computers which perform me of the DBMS functions h</p><p>　　This is one of the most common misconceptions about database management systems that are used in personal computers. Thorough

43、ly comprehensive and sophisticated business systems can be developed in dBASE, Paradox and other DBMSs. However, they are created by experienced programmers using the DBMS's own programming language. That is not the

44、same as users who create and manage personal files that are not part of the mainstream company system. </p><p>　　Transaction Management of Database   </p><p>　　The objective of lo

45、ng-duration transactions is to model long-duration, interactive Database access sessions in application environments. The fundamental assumption about short-duration of transactions that underlies the traditional model o

46、f transactions is inappropriate for long-duration transactions. The implementation of the traditional model of transactions may cause intolerably long waits when transactions aleph to acquire locks before accessing data,

47、 and may also cause a large amount of wor</p><p>　　Version System Management of Database    </p><p>　　Despite a large number of proposals on version support in the context of comp

48、uter aided design and software engineering, the absence of a consensus on version semantics has been a key impediment to version support in database systems. Because of the differences between files and databases, it is

49、intuitively clear that the model of versions in database systems cannot be as simple as that adopted in file systems to support software engineering.For data-bases, it may be necessary to manage not only</p><p

50、>　　There is no consensus of the definition of the term “management information system”. Some writers prefer alternative terminology such as “information processing system”, “information and decision system”, “organiza

51、tional information system”, or simply “information system” to refer to the computer-based information processing system which supports the operations, management, and decision-making functions of an organization. This te

52、xt uses “MIS” because it is descriptive and generally understood; </p><p>　　A definition of a management information system, as the term is generally understood, is an integrated, user-machine system for pro

53、viding information to support operations, management, and decision-making functions in an organization. The system utilizes computer hardware and software; manual procedures; models for analysis planning, control and dec

54、ision making; and a database. The fact that it is an integrated system does not mean that it is a single, monolithic structure; rather, it means that</p><p>　　Conceptually, a management information can exist

55、 without computer, but it is the power of the computer which makes MIS feasible. The question is not whether computers should be used in management information system, but the extent to which information use should be co

56、mputerized. The concept of a user-machine system implies that some tasks are best performed by humans, while others are best done by machine. The user of an MIS is any person responsible for entering input data, instruct

57、ing the syst</p><p>　　User-machine interaction is facilitated by operation in which the user’s input-output device ( usually a visual display terminal) is connected to the computer. The computer can be a per

58、sonal computer serving only one user or a large computer that serves a number of users through terminals connected by communication lines. The user input-output device permits direct input of data and immediate output of

59、 results. For instance, a person using the computer interactively in financial planning poses “</p><p>　　The computer-based user-machine characteristics of an MIS affect the knowledge requirements of both sy

60、stem developer and system user. “computer-based” means that the designer of a management information system must have a knowledge of computers and of their use in processing. The “user-machine” concept means the system d

61、esigner should also understand the capabilities of humans as system components (as information processors) and the behavior of humans as users of information.</p><p>　　Information system applications should

62、not require users to be computer experts. However, users need to be able to specify their information requirements; some understanding of computers, the nature of information, and its use in various management function a

63、ids users in this task.</p><p>　　Management information system typically provide the basis for integration of organizational information processing. Individual applications within information systems are dev

64、eloped for and by diverse sets of users. If there are no integrating processes and mechanisms, the individual applications may be inconsistent and incompatible. Data item may be specified differently and may not be compa

65、tible across applications that use the same data. There may be redundant development of separate applicati</p><p>　　The first step in integration of information system applications is an overall information

66、system plan. Even though application systems are implemented one at a time, their design can be guided by the overall plan, which determines how they fit in with other functions. In essence, the information system is des

67、igned as a planed federation of small systems.</p><p>　　Information system integration is also achieved through standards, guidelines, and procedures set by the MIS function. The enforcement of such standard

68、s and procedures permit diverse applications to share data, meet audit and control requirements, and be shares by multiple users. For instance, an application may be developed to run on a particular small computer. Stand

69、ards for integration may dictate that the equipment selected be compatible with the centralized database. The trend in informatio</p><p>　　The term “information” and “data” are frequently used interchangeabl

70、y; However, information is generally defined as data that is meaningful or useful to the recipient. Data items are therefore the raw material for producing information.</p><p>　　The underlying concept of a d

71、atabase is that data needs to be managed in order to be available for processing and have appropriate quality. This data management includes both software and organization. The software to create and manage a database is

72、 a database management system.</p><p>　　When all access to any use of database is controlled through a database management system, all applications utilizing a particular data item access the same data item

73、which is stored in only one place. A single updating of the data item updates it for all uses. Integration through a database management system requires a central authority for the database. The data can be stored in one

74、 central computer or dispersed among several computers; the overriding requirement is that there be an organizati</p><p>　　It is usually insufficient for human recipients to receive only raw data or even sum

75、marized data. Data usually needs to be processed and presented in such a way that the result is directed toward the decision to be made. To do this, processing of data items is based on a decision model. For example, an

76、investment decision relative to new capital expenditures might be processed in terms of a capital expenditure decision model. </p><p>　　Decision models can be used to support different stages in the decision

77、-making process. “Intelligence” models can be used to search for problems and/or opportunities. Models can be used to identify and analyze possible solutions. Choice models such as optimization models maybe used to find

78、the most desirable solution.</p><p>　　In other words, multiple approaches are needed to meet a variety of decision situations. The following are examples and the type of model that might be included in an MI

79、S to aid in analysis in support of decision-making; in a comprehensive information system, the decision maker has available a set of general models that can be applied to many analysis and decision situations plus a set

80、of very specific models for unique decisions. Similar models are available for planning and control. The set of</p><p>　　Models are generally most effective when the manager can use interactive dialog to bui

81、ld a plan or to iterate through several decision choices under different conditions.</p><p><b>　　中文譯文：</b></p><p>　　《數(shù)據(jù)庫幸存者：成為一個(gè)搖滾明星》</p><p>　　眾所周知，數(shù)據(jù)庫是邏輯上相關(guān)的數(shù)據(jù)元的匯集.這些數(shù)據(jù)

82、元可以按不同的結(jié)構(gòu)組織起來，以滿足單位和個(gè)人的多種處理和檢索的需要。數(shù)據(jù)庫本身不是什么新鮮事——早期的數(shù)據(jù)庫鑿在石頭上，記在名冊上，以及寫在索引卡中。而現(xiàn)在，數(shù)據(jù)庫普遍記錄在可磁化的介質(zhì)上，并且需要用計(jì)算機(jī)程序來執(zhí)行必需的存儲(chǔ)和檢索操作。</p><p>　　如下所述，所有數(shù)據(jù)庫（最簡單的除外）中都有復(fù)雜的數(shù)據(jù)關(guān)系及其鏈接。處理與創(chuàng)建、訪問以及維護(hù)數(shù)據(jù)庫記錄有關(guān)的復(fù)雜任務(wù)的系統(tǒng)軟件包叫做數(shù)據(jù)庫管理系統(tǒng)（DBMS）

83、。DBMS軟件包中的程序在數(shù)據(jù)庫與其用戶間建立接口。（這些用戶可以是應(yīng)用程序員、管理員、及其他需要信息的人員和各種操作系統(tǒng)程序）。</p><p>　　DBMS可組織、處理和表示從數(shù)據(jù)庫中選出的數(shù)據(jù)元。該功能使決策者能搜索、探查和查詢數(shù)據(jù)庫的內(nèi)容，從而對在正規(guī)報(bào)告中沒有的、不再出現(xiàn)的且無法預(yù)料的問題作出回答。這些問題最初可能是模糊的并且（或者）是定義不恰當(dāng)?shù)?，但是人們可以瀏覽數(shù)據(jù)庫直到獲得所需的信息。簡言之，DB

84、MS將“管理”存儲(chǔ)的數(shù)據(jù)項(xiàng)，并從公共數(shù)據(jù)庫中匯集所需的數(shù)據(jù)項(xiàng)以回答非程序員的詢問。在面向文件的系統(tǒng)中，需要特定信息的用戶應(yīng)將他們的要求傳送給程序員。該程序員在時(shí)間允許時(shí)，將編寫一個(gè)或多個(gè)程序以提取數(shù)據(jù)和準(zhǔn)備信息。然而，DBMS的可用性為用戶提供了一個(gè)更快的替代通信通道。</p><p>　　如果數(shù)據(jù)庫管理系統(tǒng)提供一種方法來相互作用地進(jìn)入和修改數(shù)據(jù)庫，同時(shí)查詢數(shù)據(jù)庫，這種方法就為管理個(gè)人數(shù)據(jù)庫創(chuàng)造了條件。但是，它不

85、能自動(dòng)留下一串查賬行動(dòng)，也不能在多用戶組織中提供那種必要的控制。只有當(dāng)一套應(yīng)用程序?yàn)槊恳粋€(gè)數(shù)據(jù)進(jìn)入和修改功能設(shè)定客戶規(guī)格時(shí)，才有可能得到這些控制。    </p><p>　　當(dāng)前，執(zhí)行數(shù)據(jù)庫系的一些功能的個(gè)人計(jì)算機(jī)軟件一直很流行。個(gè)人計(jì)算機(jī)是供個(gè)人信息存儲(chǔ)和處理而用。這些機(jī)器也廣泛地被一些小企業(yè)、職業(yè)家如建筑師，醫(yī)師、工程師、律師等等所使用。從使用意圖的性質(zhì)看，這些機(jī)器上

86、的數(shù)據(jù)庫系統(tǒng)沒有正式數(shù)據(jù)庫系統(tǒng)的一些要求。由于不需要數(shù)據(jù)分享，也不需要同時(shí)操作。軟件也就不那么復(fù)雜。安全和整體維護(hù)也不那么重要，甚至沒有隨著數(shù)據(jù)容量變性能效率也不那么重要。事實(shí)上，數(shù)據(jù)庫系統(tǒng)唯一重要的方面是數(shù)據(jù)獨(dú)立。正如以前所述，數(shù)據(jù)獨(dú)立是指在輔助存儲(chǔ)器上，應(yīng)用程序和用戶詢問不必知道數(shù)排的物理組織。這個(gè)方面的重要性，尤其對個(gè)人計(jì)算機(jī)用戶來說，大大簡化了數(shù)據(jù)庫的使用。用戶能夠高層次地存儲(chǔ)，存取和操縱數(shù)據(jù)，并且能夠完全不受數(shù)據(jù)組織低層次細(xì)節(jié)

87、的影響。在這里我們將不討論一個(gè)特定個(gè)人計(jì)算機(jī)數(shù)據(jù)庫管理系統(tǒng)軟件包細(xì)節(jié)。我們將在下面總結(jié)一下個(gè)人計(jì)算機(jī)數(shù)據(jù)庫軟件系統(tǒng)的優(yōu)缺點(diǎn)： </p><p>　　最明顯的積極方面是軟件的用戶友好型。一個(gè)事先不了解計(jì)算機(jī)知識(shí)的用戶能夠使用該系統(tǒng)來儲(chǔ)存?zhèn)€人和職業(yè)數(shù)據(jù)，檢索和執(zhí)行有關(guān)處理。當(dāng)然，用戶應(yīng)該使自己對軟件質(zhì)量感到滿足，高質(zhì)量的軟件仗數(shù)據(jù)的出錯(cuò)率減少從而使數(shù)據(jù)投資 得到保護(hù)。</p><p>

88、;　　對于完成應(yīng)用的程序員而言，這個(gè)優(yōu)點(diǎn)存在于支持這些系統(tǒng)所提供的在輸入屏幕產(chǎn)生，輸出報(bào)告產(chǎn)生方面的應(yīng)用發(fā)展。    </p><p>　　主要消極點(diǎn)是缺少數(shù)據(jù)保護(hù)特征。除非被譯成密碼，數(shù)據(jù)不能被任何接觸機(jī)器的人所存取。數(shù)據(jù)也能由于錯(cuò)誤或被懷有惡意的人毀掉。以個(gè)人計(jì)算機(jī)為基礎(chǔ)的許多系統(tǒng)的第二個(gè)缺點(diǎn)是效率方面的缺點(diǎn)。如果數(shù)據(jù)發(fā)展到幾千個(gè)記錄，效率問題可能是一個(gè)難關(guān)。 

89、;    </p><p>　　由于數(shù)據(jù)容量的增長是一種發(fā)展趨勢，所以應(yīng)該考慮在較大的權(quán)器上獲得相同或相容的軟件。    </p><p>　　這是對用個(gè)人計(jì)算機(jī)數(shù)據(jù)庫管理系統(tǒng)的最常見的錯(cuò)誤概念之一：高綜合和復(fù)雜的商業(yè)系統(tǒng)可以在dBASE，Paradox和其它數(shù)據(jù)庫譽(yù)理系統(tǒng)中得以發(fā)展。但是，這些商業(yè)系統(tǒng)是由富有經(jīng)驗(yàn)的程序

90、設(shè)計(jì)員通過使用數(shù)據(jù)庫管理系統(tǒng)專用的程序語言而建立的，這與建立和管理不是公司主要系統(tǒng)部分的個(gè)人文件的用戶有所不同。</p><p>　　數(shù)據(jù)庫的業(yè)務(wù)管理   </p><p>　　長期業(yè)務(wù)的目的是：在應(yīng)用環(huán)境中模擬長期的、相互作用的數(shù)據(jù)庫存取對話傳統(tǒng)業(yè)務(wù)模式中關(guān)于短期業(yè)務(wù)的基本假設(shè)對于長期業(yè)務(wù)是不適用的。在存取數(shù)據(jù)前，當(dāng)交易試圖獲得鎖定時(shí)，傳統(tǒng)模式業(yè)務(wù)的執(zhí)行可能

91、會(huì)引起長期等待。也可能引起大量工作丟失，當(dāng)交易隨著用戶產(chǎn)生的障礙或系統(tǒng)失靈被放棄時(shí)。     </p><p>　　業(yè)務(wù)模式的目的是提供嚴(yán)格的基礎(chǔ)，在潛系統(tǒng)失靈的情況下，為了保持一套多個(gè)同時(shí)讀寫存取及數(shù)據(jù)庫一致性，業(yè)務(wù)模式自動(dòng)實(shí)行一個(gè)標(biāo)準(zhǔn)。在傳統(tǒng)業(yè)務(wù)中采取的一致性標(biāo)準(zhǔn)是一種串行概念。在傳統(tǒng)數(shù)據(jù)庫系統(tǒng)中為自動(dòng)并行控制，通過使用鎖定而實(shí)行串行，并為了從系統(tǒng)失靈中自動(dòng)恢復(fù)而聯(lián)機(jī)。

92、一個(gè)不能為實(shí)施自動(dòng)數(shù)據(jù)庫一致性而提供基礎(chǔ)的業(yè)務(wù)不是一個(gè)真業(yè)務(wù)。確切地說，一個(gè)長期業(yè)務(wù)不必非采用串行作為它的一致標(biāo)準(zhǔn)，但是，必須有一些一致性的標(biāo)準(zhǔn)。</p><p>　　數(shù)據(jù)庫的文本管理     </p><p>　　在計(jì)算機(jī)輔助設(shè)計(jì)和軟件工程的環(huán)境影響下，盡管對本文支持有許多建議，但對本文語義的意見不一致一直大大妨礙了數(shù)據(jù)庫系統(tǒng)的文本支持。由于文件和

93、數(shù)據(jù)庫之間的差別，從直觀上很清楚數(shù)據(jù)庫系統(tǒng)的文本模式不可能與文件系統(tǒng)所采用的支持軟件工程的文本模式同樣簡單。對于數(shù)據(jù)庫來說，有必要不僅管理單個(gè)事務(wù)的文本（例如，一個(gè)軟件模塊，一份文件等等）而且也要管理許多事務(wù)（例如一個(gè)復(fù)合文件，一個(gè)用戶手冊等等）甚至還要管理數(shù)據(jù)庫構(gòu)圖的文本。（例如一個(gè)表格和或一個(gè)類別，許多表格，許多類別）。     </p><p>　　從廣義上說，在文本

94、的研究和發(fā)展方面有三個(gè)方向。第一，是參數(shù)文本的概念，即設(shè)計(jì)和任一種文本系統(tǒng)，其行為可能通過調(diào)節(jié)系統(tǒng)參數(shù)而改制。鑒于對文本的每一個(gè)單方而有許多似乎可行的選擇這一事實(shí)，這可能是唯一可行的方法。第二個(gè)方向是重訪文本每一個(gè)方面的可一行的選擇，目的在于將其中或者是不實(shí)用的或者有毛病的選擇丟掉。第三個(gè)方向是對語義進(jìn)行研究并執(zhí)行描述一大批物體和數(shù)據(jù)庫的構(gòu)圖。</p><p>　　對于“管理信息系統(tǒng)”并沒有一致的定義。一些作者喜

95、歡用其他術(shù)語代替，例如：“信息處理系統(tǒng)”“信息與決策系統(tǒng)”“組織信息系統(tǒng)”，或者干脆將“信息系統(tǒng)”用組織內(nèi)具有支持操作、管理、決策職能的計(jì)算機(jī)信息處理系統(tǒng)代替。這篇文章使用“管理信息系統(tǒng)”一詞，是因?yàn)樗峭ㄋ滓锥?，?dāng)涉及組織信息系統(tǒng)時(shí)也常用“信息系統(tǒng)”代替“管理信息系統(tǒng)”。</p><p>　　一個(gè)管理信息系統(tǒng)的定義，通常被理解為：一種集成用戶機(jī)器系統(tǒng)，為組織提供信息支持運(yùn)作、管理、決策職能。該信息系統(tǒng)利用計(jì)算

96、機(jī)硬件和軟件；手工處理程序；模擬分析法計(jì)劃、控制和決策；和數(shù)據(jù)庫。事實(shí)上，它是一個(gè)集成系統(tǒng)并不意味著它是單一的，單塊集成結(jié)構(gòu)；相反，它意味著零件適合加入整體設(shè)計(jì)。內(nèi)容定義如下：計(jì)算機(jī)為主的用戶機(jī)器系統(tǒng)。</p><p>　　理論上，管理信息系統(tǒng)可以脫離計(jì)算機(jī)上而存在，但是計(jì)算機(jī)的存在可以讓管理信息系統(tǒng)可行。問題不是計(jì)算機(jī)是否被使用在管理信息系統(tǒng)中，而是信息的使用被計(jì)算機(jī)化的程度。用戶機(jī)器系統(tǒng)的概念暗示了， 一些任

97、務(wù)最好由人執(zhí)行， 其他的最好由機(jī)器做。MIS的使用者是那些負(fù)責(zé)輸入輸入數(shù)據(jù)、指示系統(tǒng)或運(yùn)用系統(tǒng)信息產(chǎn)品的人。因?yàn)樵S多問題，用戶和計(jì)算機(jī)建立了一個(gè)聯(lián)合系統(tǒng)，其結(jié)果通過一套在計(jì)算機(jī)和用戶之間的相互作用得到。</p><p>　　用戶機(jī)器的相互作用是由用戶連接在計(jì)算機(jī)上的輸入-輸出設(shè)備（通常是一個(gè)視覺顯示終端）推動(dòng)的。計(jì)算機(jī)可以使一臺(tái)個(gè)人機(jī)器服務(wù)于一名用戶或者一臺(tái)大規(guī)模的機(jī)器為一定數(shù)量通過終端由通信線路連接的用戶服務(wù)。

98、用戶輸入-輸出設(shè)備允許直接輸入數(shù)據(jù)和緊接著輸出結(jié)果。例如：一個(gè)人使用計(jì)算機(jī)交互的在金融理財(cái)上通過在終端鍵盤輸入提交“如果什么，怎么辦？”之類的問題，結(jié)果幾秒鐘后便被顯示在屏幕上。</p><p>　　以MIS計(jì)算機(jī)為主的用戶機(jī)器特征影響系統(tǒng)開發(fā)商和系統(tǒng)用戶的知識(shí)要求?！坝?jì)算機(jī)為主”意味著管理信息系統(tǒng)的設(shè)計(jì)者必須擁有計(jì)算機(jī)和對處理有用的知識(shí)?！坝脩魴C(jī)器”的概念意味著系統(tǒng)設(shè)計(jì)者也應(yīng)該了解人作為系統(tǒng)組成部分（信息處理器

99、）的能力和人作為信息使用者的行為。</p><p>　　信息系統(tǒng)的應(yīng)用不應(yīng)該要求用戶成為計(jì)算機(jī)專家。但是，用戶需要能夠詳細(xì)說明他們的信息要求；對計(jì)算機(jī)的一些理解、信息的本質(zhì)，和對各種各樣管理功能的利用將幫助用戶完成任務(wù)。</p><p>　　管理信息系統(tǒng)代表性地為集成組織信息處理提供依據(jù)。信息系統(tǒng)內(nèi)部各自的應(yīng)用則由不同批次的用戶開發(fā)。如果沒有集成的處理和機(jī)制，各自的應(yīng)用也許無法協(xié)調(diào)一致和相