【正文】 Database Management Systems A database (sometimes spelled data base) is also called an electronic database , referring to any collection of data, or information, that is specially organized for rapid search and retrieval by a puter. Databases are structured to facilitate the storage, retrieval , modification, and deletion of data in conjunction with various dataprocessing operations .Databases can be stored on magic disk or tape, optical disk, or some other secondary storage device. A database consists of a file or a set of files. The information in these files may be broken down into records, each of which consists of one or more fields. Fields are the basic units of data storage , and each field typically contains information pertaining to one aspect or attribute of the entity described by the database . Using keywords and various sorting mands, users can rapidly search , rearrange, group, and select the fields in many records to retrieve or create reports on particular aggregate of data. Complex data relationships and linkages may be 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 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 needs, and various OS programs.) A DBMS can organize, process, and present selected data elements form the database. This capability enables decision makers to search, probe, and query database contents in order to extract answers to nonrecurring and unplanned questions that aren’t available in regular reports. These questions might initially be vague and/or poorly defined ,but people can “browse” through the database until they have the needed information. In short, the DBMS will “manage” the stored data items and assemble the needed items from the mon database in response to the queries of those who aren’t programmers. A database management system (DBMS) is posed of three major parts:(1)a storage subsystem that stores and retrieves data in files。(2) a modeling and manipulation subsystem that provides the means with which to organize the data and to add , delete, maintain, and update the data。 揚(yáng)州大學(xué)計(jì)算機(jī)專業(yè) 畢業(yè)設(shè)計(jì) (外文翻譯 ) 2 Managers: who require more uptodata information to make effective decision Customers: who demand increasingly sophisticated information services and more current information about the status of their orders, invoices, and accounts. Users: who find that they can develop custom applications with database systems in a fraction of the time it takes to use traditional programming languages. Organizations : that discover information has a strategic value。s heart to suffer a fatal arrest. Ironically, although most users are now aware of hackers, they still do not realize how susceptible their database servers are to hack attacks. Thus, this article presents a description of the primary methods of attacking database servers (also known as SQL servers) and shows you how to protect yourself from these attacks. You should note this information is not new. Many technical white papers go into great detail about how to perform SQL attacks, and numerous vulnerabilities have been posted to security lists that describe exactly how certain database applications can be exploited. This article was written for the curious nonSQL experts who do not care to know the details, and as a review to those who do use SQL regularly. What Is a SQL Server? A database application is a program that provides clients with access to data. There are many variations of this type of application, ranging from the expensive enterpriselevel Microsoft SQL Server to the free and open source mySQL. Regardless of the flavor, most database server applications have several things in mon. First, database applications use the same general programming language known as SQL, or Structured Query Language. This language, also known as a fourthlevel language due to its simplistic syntax, is at the core of how a client municates its requests to the server. Using SQL in its simplest form, a programmer can select, add, update, and delete information in a database. However, SQL can also be used to create and design entire da