【正文】 e system designer should also understand the capabilities of humans as system ponents (as information processors) and the behavior of humans as users of information. Information system applications should not require users to be puter experts. However, users need to be able to specify their information requirements。 and a database. The fact that it is an integrated system does not mean that it is a single, monolithic structure。 manual procedures。s own programming language. That is not the same as users who create and manage personal filesthat are not part of the mainstream pany system． Transaction Management of Database The objective of longduration transactions is to model longduration, interactive Database access sessions in application environments． The fundamental assumption about shortduration of transactions that underlies the traditional model of transactions is inappropriate for longduration transactions． The implementation of the traditional 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 userinitiated aborts or system failure situations． The objective of a transaction model is to provide 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 situations． The consistency criterion adopted for traditional transactions is the notion of scrializability． Scrializability is enforced in conventional database systems through the use of locking for automatic concurrency control, and logging for automatic recovery from system failure situations． A transaction”that doesn’t provide a basis for automatically enforcing database consistency is not really a transaction. To be sure, a longduration transaction need not adopt serializability as its consistency criterion． However. there must be some consistcricv criterion． Version System Management of Database Despite a large number of proposals on version support in the context of puter 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 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, anizational information system, or simply information system to refer to the puterbased information processing system which supports the operations, management, and decisionmaking functions of an anization. This text uses “MIS” because it is descriptive and generally understood。 DATABASE MANAGEMENT SYSTEMS （ DBMS ） AND MANAGEMENT INFORMATION SYSTEM（ MIS） You know that a database is a collection of logically