计算机英语(第三版)7—7.2作者：刘兆毓、郑家农(普通高等教育“十一五”国家级规划教材).pptVIP

PART Ⅲ APPLICATIONS CHAPTER 7 DATABASE 7.2 SQL AND SQL SERVER ;*Main point; IBM invented a computer language back in the 1970s designed specifically for database queries called SEQUEL; those letters stand for Structured English Query Language. Over time, the language has been added to so that it is not just a language for queries, but can also build databases and manage the database engine’s security. IBM released SEQUEL into the public domain, where it became known as SQL. Because of this heritage you can pronounce it “sequel” or spell it out “S-Q-L.” There are various versions of SQL used in today’s database engines. ;*?1;*?2;Any client/server data-based system consists of the following components: ● The server—A collection of data items and supporting objects organized and presented to facilitate services, such as searching, sorting, recombining, retrieving, updating, and analyzing data. The database consists of the physical storage of data and the database services. All data access occurs through the server; the physical data is never accessed directly by the client. ;● The client—A software program that might be used interactively by a person or that could be an automated process. This includes all software that interacts with the server, either requesting data from or sending data to the database. Examples are management utilities (those that are part of the SQL Server product as well as those bought separately), ad hoc query and reporting software, custom applications, off-the-shelf applications, and Web server- based applications.［2］ ;*?3*?4;;3. SQL Server Platforms SQL Server runs on the operating systems shown in Fig.7-4. The SQL Server version 7 server software runs only on the Windows 32-bit API-based operating systems, but you can use all of the operating system platforms to create and execute client applications. ;Fig.7-4 Operating systems on which the SQL Server client and server