【正文】 f such systems, and formed their own panies to mercialize the work but with an SQL interface. Sybase, Informix, NonStop SQL and eventually Ingres itself were all being sold as offshoots to the original INGRES product in the 1980s. Even Microsoft SQL Server is actually a rebuilt version of Sybase, and thus, INGRES. Only Larry Ellison39。s data were in a database, that person39。 for example, no two customers with the same customer numbers (key fields) can be entered into the database. See ACID properties for more information (Redundancy avoidance). 5. DBMS topics External, Logical and Internal view A database management system provides the ability for many different users to share data and process resources. But as there can be many different users, there are many different database needs. The question now is: How can a single, unified database meet the differing requirement of 機(jī)械專業(yè)中英文文獻(xiàn)翻譯 so many users? A DBMS minimizes these problems by providing two views of the database data: an external view(or User view), logical view(or conceptual view)and physical(or internal) view. The user’s view, of a database program represents data in a format that is meaningful to a user and to the software programs that process those data. That is, the logical view tells the user, in user terms, what is in the database. The physical view deals with the actual, physical arrangement and location of data in the direct access storage devices(DASDs). Database specialists use the physical view to make efficient use of storage and processing resources. With the logical view users can see data differently from how they are stored, and they do not want to know all the technical details of physical storage. After all, a business user is primarily interested in using the information, not in how it is stored. One strength of a DBMS is that while there is typically only one conceptual (or logical) and physical (or Internal) view of the data, there can be an endless number of different External views. This feature allows users to see database information in a more businessrelated way rather than from a technical, processing viewpoint. Thus the logical view refers to the way user views data, and the physical view to the way the data are physically stored and processed... DBMS features and capabilities Alternatively, and especially in connection with the relational model of database management, the relation between attributes drawn from a specified set of domains can be seen as being primary. For instance, the database might indicate that a car that was originally red might fade to pink in time, provided it was of some particular make with an inferior paint job. Such higher arity relationships provide information on all of the underlying domains at the same time, with none of them being privileged above the others. DBMS simple definition Data base management system is the system in which related data is stored in an efficient and pact manner. Efficient means that the data which is stored in the DBMS is accessed in very quick time and pact means that the data which is stored in DBMS covers very less space in puter39。s online backup services, many services are beginning to move to web based services due t。s GMail, Microsoft39。s data, and on the application39。s papers on System R, and beat IBM to market when the first version was released in 1978. Stonebraker went on to apply the lessons from INGRES to develop a new database, Postgres, which is now known as PostgreSQL. PostgreSQL is often used for global mission critical applications (the . and .info domain name registries use it as their primary data store, as do many large panies and financial institutions). In Sweden, Codd39。s own Alpha language, but has since been corrupted to follow SQL, thus violating much the same concepts of the relational model as SQL itself. IBM itself did one test implementation of the relational model, PRTV, and a production one, Business System 12, both now discontinued. Honeywell did MRDS for Multics, and now there are two new implementations: Alphora Dataphor and Rel. All other DBMS implementations usually 機(jī)械專業(yè)中英文文獻(xiàn)翻譯 called relational are actually SQL DBMSs. In 1968, the University of Michigan began development of the Micro DBMS relational database management system. It was used to manage very large data sets by the US Department of Labor, the Environmental Protection Agency and researchers from University of Alberta, the University of Michigan and Wayne State University. It ran on mainframe puters using Michigan Terminal System. The system remained in production until 1996. End 1970s SQL DBMS IBM started working on a prototype system loosely based on Codd39。s 1973 Turing Award award presentation was The Programmer as Navigator. IMS is classified as a hierarchical database. IMS and IDMS, both CODASYL databases, as well as CINCOMs TOTAL database are classified as work databases. 1970s Relational DBMS Edgar Codd worked at IBM in San Jose, California, in one of their offshoot offices that was primarily involved in the development of hard disk systems. He was unhappy with the navigational model of the Codasyl approach, notably the lack of a search facility which was being increasingly useful. In 1970, he wrote a number of papers that outlined a new approach to database construction that eventually culminated in the groundbreaking A Relational Model of Data for Large Shared Data Banks. In this paper, he described a new system for storing and working with large databases. Instead of records being stored in some sort of linked list of freeform records as in Codasyl, 機(jī)械專業(yè)中英文文獻(xiàn)翻譯 Codd39。機(jī)械專業(yè)中英文文獻(xiàn)翻譯 英文原文 Database management system management system A Database Management System (DBMS) is a set of puter programs that controls the creation, maintenance, and the use of a database. It allow