【正文】 gn 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 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 databases, it may be necessary to manage not only versions of single objects (. a software module, document, but also versions of a collection of objects (. a pound document, a user manual， etc． and perhaps even versions of the schema of database (. a table or a class, a collection of tables or classes)． Broadly, there are three directions of research and development in versioning． First is the notion of a parameterized versioning， that is, designing and implementing a versioning system whose behavior may be tailored by 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 versioning． The second is to revisit these plausible choices for every aspect of versioning, with the view to discarding some of themes 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 such as information processing system, information and decision system, organizational information system, or simply information system to refer to the puterbased information processing system which supports the operations, management, and decisionmaking functions of an organization. This text uses “MIS” because it is descriptive and generally understood。數(shù)據(jù)可能被放在一個(gè)中央計(jì)算機(jī)里或者被分散在幾個(gè)計(jì)算機(jī)之中；最重要的 要求是擁有一個(gè)組織功能來執(zhí)行控制。 信息系統(tǒng)集成也通過標(biāo)準(zhǔn)，指南，和程序達(dá)到，被留作管理信息系統(tǒng)的功能之用。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。 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。但是，這些商業(yè)系統(tǒng)是由富有經(jīng)驗(yàn)的程序設(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。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。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(duì)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。 DBMS 軟件包中的程序在數(shù)據(jù)庫與其用戶間建立接口。由于不需要數(shù)據(jù)分享，也不需要同時(shí)操作。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)。 從廣義上說，在文本的研究和發(fā)展方面有三個(gè)方向。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。 信息系統(tǒng)應(yīng)用集成的第一步是一個(gè)整體信息系統(tǒng)計(jì)劃。當(dāng)使用數(shù)據(jù)庫的所有途徑都是通過數(shù)據(jù)庫管理系統(tǒng)被控制，所有應(yīng)用都利用一個(gè)特殊數(shù)據(jù)項(xiàng)來存取被存放在唯一一個(gè)地方的相同的數(shù)據(jù)項(xiàng)。 在不同的情況下，當(dāng)管理人員可以使用交互式的對(duì)話建立一個(gè)計(jì)劃或者通過幾個(gè)決定選擇重復(fù)敘述，模型一般是最有效的 。 some understanding of puters, the nature of information, and its use in various management function aids users in this task. Integrated system 集成系統(tǒng) Management information system typically provide the basis for integration of organizational information 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 inpatible. Data item may be specified differently and may not be patible 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 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 information 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 control requirements, and be shares by multiple users. For instance, an application may be developed to run on a particular small puter. Standards for integration may dictate that the equipment selected be patible with the centralized database. The trend