数据库管理系统(DBMS)和管理信息系统(MIS)外文文献翻译、中英文翻译

1、DATABASE MANAGEMENT SYSTEMS（DBMS）AND MANAGEMENT INFORMATION SYSTEM（MIS）You know that a database is a collection of logically related data elements that may be structured in various ways to meet the multiple processing and retrieval needs of organizations and individualsThere s nothing new about data

2、basesearly ones1 were chiseled in stone，penned on scrolls，and written on index cardsBut now databases are commonly recorded on magnetizable media，and computer programs are required to perform the necessary storage and retrieval operationsYoull see in the following pages that complex data relationshi

3、ps and linkages may be found in all but the simplest databases2The system software package that handles the difficult tasks associated with creating，accessing，and maintaining database records is called a database management system（DBMS）The programs in a DBMS package establish an interface between th

4、e database itself and the users of the database（These users may be applications programmers，managers and others with information needs，and various OS programs）A DBMS can organize，process，and present selected data elements from the databaseThis capability enables decision makers to search，probe，and q

5、uery database contents in order to extract answers to nonrecurring and unplanned questions that arent available in regular reports3These questions might initially be vague and / or poorly defined，but people can“browse”through the database until they have the needed informationIn short，the DBMS will“

6、manage”the stored data items and assemble the needed items from the common database in response to the queries of those who arent programmersIn a file-oriented system，users needing special information may communicate their needs to a programmer，who，when time permits，will write one or more programs t

7、o extract the data and prepare the information4The availability of a DBMS，however，offers users a much faster alternative communications path.If 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 do

8、es not automatically leave an audit trail of actions and does not provide the kinds of controla 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. Software for personal computers which

9、perform me of the DBMS functions have been very popular arsenal computers were intended for use by individuals for personal information storage and process- These machines have also been used extensively small enterprises, professionals like doctors, acrylics, engineers, lawyers and so on By the nat

10、ure of. intended usage, database systems on these machines except from several of the requirements of full doge database systemsSince data sharing is not：Tended, concurrent operations even less so, the) fewer can be less complex. Security and integrity7aintenance are de-emphasized or absent. As data

11、-) limes will be small, performance efficiency Is also important. In fact, the only aspect of a database system that is Important is data Independence. Data-.dependence, as stated earlier. Means that applicant programs and user queries need not recognizantphysical organization of data on secondary s

12、torage. The importance of this aspect, particularly for the personal computer user, is that this greatly simplifies database usage. The user can store, access and manipulate data at a high level (close to the application) and be totally shielded from the low level (close to the machine) details of d

13、ata organization. We will not discuss details of specific PC DBMS software packages hereLet us summarize in the following the strengths and weaknesses of personal computer data-base software systems： The most obvious positive factor is the user friendliness of the software. A user with no prior comp

14、uter background would be able to use the system to store personal and professional data, retrieve and perform relayed processing. The user should, of course, satiety himself about the quality of software and the freedom from errors (bugs) so that invest-merits in data arc protected. For the programm

15、er implementing applications with them, the advantage lies in the support for applications development in terms of input screen generations, output report generation etcoffered by theses stems The main negative point concerns absence of data protection featuresUnless encrypted, data cane accessed by

16、 whoever has access to the machine Data can be destroyed through mistakes or maliciousintent. The second weakness of manv of the PC-basedsystems is that of performance. If data volumes growup to a few thousands of records，performance couldbe a bottleneck For organization where growth in data volumes

17、is expected, availability of, the same or compatiblesoftware on large machines should be considered.This is one of the most common misconceptionsabout database management systems that are used inpersonal computersThoroughly comprehensive andsophisticated business systems can be developed indBASh, Pa

18、radox and other DBMSsHowever, theyare created by experienced programmers using theDBMSs own programming language. That is not the same as users who create and manage personal filesthat are not part of the mainstream company systemTransaction Management of DatabaseThe objective of long-duration trans

19、actions is to model long-duration, interactive Database access sessions in application environmentsThe fundamental assumption about short-duration of transactions that underlies the traditional model of transactions is inappropriate for long-duration transactionsThe implementation of the traditional

20、 model of transactions may cause intolerably long waits when transactions aleph to acquire locks before accessing data, and may also cause a large amount of work to be lost when transactions are backed out in response to user-initiated aborts or system failure situations The objective of a transacti

21、on model is to pro-vide a rigorous basis for automatically enforcing criterion for database consistency for a set of multiple concurrent read and write accesses to the database in the presence of potential system failure situationsThe consistency criterion adopted for traditional transactions is the

22、 notion of scrializabilityScrializa-bility is enforced in conventional database systems through the use of locking for automatic concurrency control, and logging for automatic recovery from system failure situationsA transaction”that doesnt provide a basis for automatically enforcing data-base consi

23、stency is not really a transaction. To be sure, a long-duration transaction need not adopt seri-alizability as its consistency criterionHowever. there must be some consistcricv criterionVersion System Management of Database Despite a large number of proposals on version support in the context of com

24、puter aided design and software engineering, the absence of a consensus on version semantics has been a key impediment to version support in database systemsBecause of the differences between files and databases, it is intuitively clear that the model of versions in database systems cannot be as sim

25、ple as that adopted in file systems to support software engineeringFor data-bases, it may be necessary to manage not only versions of single objects (e.g. a software module, document, but also versions of a collection of objects (e.g. a compound document, a user manual，etcand perhaps even versions o

26、f the schema of database (c.g. a table or a class, a collection of tables or classes)Broadly, there are three directions of research and development in versioningFirst is the notion of a parameterized versioning，that is, designing and implementing a versioning system whose behavior may be tailored b

27、y adjusting system parameters This may be the only viable approach, in view of the fact that there are various plausible choices for virtually every single aspect of versioningThe second is to revisit these plausible choices for every aspect of versioning, with the view to discarding some of themes

28、either impractical or flawed. The third is the investigation into the semantics and implementation of versioning collections of objects and of versioning the database sche There is no consensus of the definition of the term management information system. Some writers prefer alternative terminology s

29、uch as information processing system, information and decision system, organizational 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 text u

30、ses “MIS” because it is descriptive and generally understood; it also frequently uses “information system” instead of “MIS” to refer to an organizational information system.A definition of a management information system, as the term is generally understood, is an integrated, user-machine system for

31、 providing 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 decision making; and a database. The fact that it is an integrated system does

32、not mean that it is a single, monolithic structure; rather, it means that the parts fit into an overall design. The elements of the definition are highlighted below. Computer-based user-machine systemConceptually, a management information can exist without computer, but it is the power of the comput

33、er 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 computerized. The concept of a user-machine system implies that some tasks are best performed by humans, while others are best done by

34、 machine. The user of an MIS is any person responsible for entering input data, instructing the system, or utilizing the information output of the system. For many problems, the user and the computer form a combined system with results obtained through a set of interactions between the computer and

35、the user.User-machine interaction is facilitated by operation in which the users input-output device( usually a visual display terminal) is connected to the computer. The computer can be a personal computer serving only one user or a large computer that serves a number of users through terminals con

36、nected by communication lines. The user input-output device permits direct input of data and immediate output of results. For instance, a person using the computer interactively in financial planning poses “what if” questions by entering input at the terminal keyboard; the results are displayed on t

37、he screen in a few second.The computer-based user-machine characteristics of an MIS affect the knowledge requirements of both system 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 processin

38、g. The “user-machine” concept means the system designer should also understand the capabilities of humans as system components (as information processors) and the behavior of humans as users of information.Information system applications should not require users to be computer experts. However, user

39、s need to be able to specify their information requirements; some understanding of computers, the nature of information, and its use in various management function aids users in this task.Integrated systemManagement information system typically provide the basis for integration of organizational inf

40、ormation processing. Individual applications within information systems are developed 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 compat

41、ible across applications that use the same data. There may be redundant development of separate applications when actually a single application could serve more than one need. A user wanting to perform analysis using data from two different applications may find the task very difficult and sometimes

42、 impossible.The first step in integration of information system applications is an overall information 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 in

43、formation system is designed as a planed federation of small systems.Information system integration is also achieved through standards, guidelines, and procedures set by the MIS function. The enforcement of such standards and procedures permit diverse applications to share data, meet audit and contr

44、ol requirements, and be shares by multiple users. For instance, an application may be developed to run on a particular small computer. Standards for integration may dictate that the equipment selected be compatible with the centralized database. The trend in information system design is toward separ

45、ate application processing form the data used to support it. The separate database is the mechanism by which data items are integrated across many applications and made consistently available to a variety of users. The need for a database in MIS is discussed below.Need for a database The term “infor

46、mation” and “data” are frequently used interchangeably; 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.The underlying concept of a database is that data needs to be managed in order

47、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 a database management system.When all access to any use of database is controlled through a database management system, all appli

48、cations utilizing a particular data item access the same data item 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 central comp

49、uter or dispersed among several computers; the overriding requirement is that there be an organizational function to exercise control.Utilization of Models It is usually insufficient for human recipients to receive only raw data or even summarized data. Data usually needs to be processed and present

50、ed 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 investment decision relative to new capital expenditures might be processed in terms of a capital expenditure decision model. Decision model

51、s can be used to support different stages in the decision-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 the most desirable solu

52、tion.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 MIS to aid in analysis in support of decision-making; in a comprehensive information system, the decision maker has available a

53、set of general models that can be applied to many analysis and decision situations plus a set of very specific models for unique decisions. Similar models are available for planning and control. The set of models is the model base for the MIS.Models are generally most effective when the manager can

54、use interactive dialog to build a plan or to iterate through several decision choices under different conditions.数据库管理系统(DBMS)和管理信息系统(MIS)众所周知，数据库是逻辑上相关的数据元的汇集。这些数据元可以按不同的结构组织起来，以满足单位和个人的多种处理和检索的需要。数据库本身不是什么新鲜事一早期的数据库凿在石头上，记在名册上，以及写在索引卡中。而现在，数据库普遍记录在可磁化的介质上，并且需要用计算机程序来执行必需的存储和检索操作。如下所述，所有数据库（最简单的除外）

55、中都有复杂的数据关系及其链接。处理与创建、访问以及维护数据库记录有关的复杂任务的系统软件包叫做数据库管理系统（DBMS）。DBMS软件包中的程序在数据库与其用户间建立接口。（这些用户可以是应用程序员、管理员、及其他需要信息的人员和各种操作系统程序）。DBMS可组织、处理和表示从数据库中选出的数据元。该功能使决策者能搜索、探查和查询数据库的内容，从而对在正规报告中没有的、不再出现的且无法预料的问题作出回答。这些问题最初可能是模糊的并且（或者）是定义不恰当的，但是人们可以浏览数据库直到获得所需的信息。简言之，DBMS将“管理”存储的数据项，并从公共数据库中汇集所需的数据项以回答非程序员的询问。在面

56、向文件的系统中，需要特定信息的用户应将他们的要求传送给程序员。该程序员在时间允许时，将编写一个或多个程序以提取数据和准备信息。然而，DBMS的可用性为用户提供了一个更快的替代通信通道（如图7-1所示）。如果数据库管理系统提供一种方法来相互作用地进入和修改数据库，同时查询数据库，这种方法就为管理个人数据库创造了条件。但是，它不能自动留下一串查账行动，也不能在多用户组织中提供那种必要的控制。只有当一套应用程序为每一个数据进入和修改功能设定客户规格时，才有可能得到这些控制。当前，执行数据库系的一些功能的个人计算机软件一直很流行。个人计算机是供个人信息存储和处理而用。这些机器也广泛地被一些小企业、职业

57、家如建筑师，医师、工程师、律师等等所使用。从使用意图的性质看，这些机器上的数据库系统没有正式数据库系统的一些要求。由于不需要数据分享，也不需要同时操作。软件也就不那么复杂。安全和整体维护也不那么重要，甚至没有随着数据容量变性能效率也不那么重要。事实上，数据库系统唯一重要的方面是数据独立。正如以前所述，数据独立是指在辅助存储器上，应用程序和用户询问不必知道数排的物理组织。这个方面的重要性，尤其对个人计算机用户来说，大大简化了数据库的使用。用户能够高层次地存储，存取和操纵数据，并且能够完全不受数据组织低层次细节的影响。在这里我们将不讨论一个特定个人计算机数据库管理系统软件包细节。我们将在下面总结一

58、下个人计算机数据库软件系统的优缺点：最明显的积极方面是软件的用户友好型。一个事先不了解计算机知识的用户能够使用该系统来储存个人和职业数据，检索和执行有关处理。当然，用户应该使自己对软件质量感到满足，高质量的软件仗数据的出错率减少从而使数据投资 得到保护。对于完成应用的程序员而言，这个优点存在于支持这些系统所提供的在输入屏幕产生，输出报告产生方面的应用发展。主要消极点是缺少数据保护特征。除非被译成密码，数据不能被任何接触机器的人所存取。数据也能由于错误或被怀有恶意的人毁掉。以个人计算机为基础的许多系 统的第二个缺点是效率方面的缺点。如果数据发展到几千个记录，效率问题可能是一个难关。 由于数据容量

59、的增长是一种发展趋势，所以应该考虑在较大的权器上获得相同或相容的软件。这是对用个人计算机数据库管理系统的最常见的错误概念之一：高综合和复杂的商业系统可以在dBASE，Paradox和其它数据库誉理系统中得以发展。但是，这些商业系统是由富有经验的程序设计员通过使用数据库管理系统专用的程序语言而建立的，这与建立和管理不是公司主要系统部分的个人文件的用户有所不同。.数据库的业务管理长期业务的目的是：在应用环境中模拟长期的、相互作用的数据库存取对话传统业务模式中关于短期业务的基本假设对于长期业务是不适用的。在存取数据前，当交易试图获得锁定时，传统模式业务的执行可能会引起长期等待。也可能引起大量工作丢失，当交易随着用户产生的障碍或系统失灵被放弃时。 业务模式的目的是提供严格的基础，在潜