Unit 5 Database.ppt

Unit 5 Database Text A Intriduction MySQL The MySQL database system uses a client-server architecture that centers around the server. MYSQL数据库系统使用的是客户端-服务器模式，这种模式以服务器为中心。 The server is the program that actually manipulates databases. 服务器是真正操作数据库的程序。 Client programs dont do that directly. 客户端程序不直接操作。 Instead, they communicate your intent to the server by means of statements written in Structured Query Language (SQL). 然而，客户端通过写结构化查询语言（SQL）语句的方法来满足你的意图。 Client programs are installed locally on the machine from which you want to access MySQL, but the server can be installed anywhere, as long as clients can connect to it. 客户端程序安装在你想访问MySQL的本地计算机上，但是服务器可以安装在任何地方，只要客户机能连接上它。 MySQL is an inherently networked database system, so clients can communicate with a server that is running locally on your machine or one that is running somewhere else, perhaps on a machine on the other side of the planet. MySQL是与生俱来地网络数据库系统，所以，客服端能和你本地机上的或者运行在其他地方的服务器通信，可能这台机器在地球的另一端。 Clients can be written for many different purposes, but each interacts with the server by connecting to it, sending SQL statements to it to have database operations performed, and receiving the statement results from it. 客户端可以写很多不同的命令，但是每次是通过连接服务器来相互影响，客户端发送SQL语句去执行数据库操作，以及从服务器接收语句结果。 One such client is the mysql program that is included in MySQL distributions. 一个这样的客户端是一个包括在MySQL分布的mysql程序。 When used interactively, mysql prompts you for a statement, sends it to the MySQL server for execution, and then displays the results. 当交互式地使用时，mysql将通过语句提醒你，把语句发送到MySQL服务器去执行，此时显示结果。 This capability makes mysql useful in its own right, but its also a valuable tool to help you with your MySQL programming activities. 这个能力使得mysql在它自己的领域非常有用，而且它也是一个有价值的工具去帮你使用你的MySQL程序。 Its often convenient to be able to quickly review the structure of a table that youre accessing from within a script, to try a statement before using it in a program to make sure that it produces the right kind of output, and so forth. 它能方便