PHP新的连接MySQL方法mysqli 摘要:介绍了在PHP5以上版本新增加的API扩展——mysqli,用以连接MySQL数据库。 在学习《AJAX and PHP Building Responsive Web Applications》的时候,书中的源代码连接MySQL数据库部分采用了mysqli的方法,假若说,您的AJAX始终不能正常显示,请根据下面的介绍进行操作,您的问题将很快得到解答。 1. 开启PHP的API支持 (1)首先修改您的php.ini的配置文件。 查找下面的语句: ;extension=php_mysqli.dll 将其修改为: extension=php_mysqli.dll (2)重新启动Apache/IIS,即可。 (3)说明:PHP需要单独的文件来支持这个扩展库,一般在PHP目录下的ext目录里能找到php_mysqli.dll文件(PHP <= 5.0.2 中是 libmysqli.dll),当然,在PHP的配置文件当中要有正确指向ext的信息(extension_dir)。假若您的PHP没有这个文件,您可以去下载PHP5的源码包。另外,这个API扩展,只能在PHP5以上版本使用。其它具体信息,请看下面。 2. mysqli身份证 mysqli是“MySQL, Improved”的缩写,该扩展仅适用于PHP 5。它能用于MySQL 4.1.1和更高版本。该扩展完全支持MySQL 5.1中采用的鉴定协议,也支持预处理语句和多语句API。此外,该扩展还提供了先进的、面向对象的编程接口。在http://php.net/mysqli上,可找到关于mysqli扩展的文档。在http://www.zend.com/php5/articles/php5-mysqli.php处,给出了一篇有用的文章。 3. mysqli预定义类 mysqli 表达了 PHP 和 MySQL 数据库之间的连接。 构造函数 mysqli - 构造一个新的 mysqli 对象 方法 autocommit - 打开或关闭自动提交的数据库选项 change_user - 改变指定的数据库连接的用户 character_set_name - 返回数据库连接的默认字符集 close - 关闭一个之前打开的连接 commit - 提交当前事务 connect - 打开一个到 MySQL 数据库服务器的新连接 debug - 执行排错操作 dump_debug_info - 取得排错信息 get_client_info - 返回客户端版本 get_host_info - 返回连接使用的类型 get_server_info - 返回 MySQL 服务器的版本 get_server_version - 返回 MySQL 服务器的版本 init - 初始化 mysqli 对象 info - 取得最近执行的查询的信息 kill - 要求服务器停止一个 mysql 线程 multi_query - 执行多个查询 more_results - check if more results exist from currently executed multi-query next_result - reads next result from currently executed multi-query options - set options ping - pings a server connection or reconnects if there is no connection prepare - prepares a SQL query query - performs a query real_connect - attempts to open a connection to MySQL database server escape_string - escapes special characters in a string for use in a SQL statement, taking into account the current charset of the connection rollback - rolls back the current transaction select_db - selects the default database set_charset - sets the default client character set ssl_set - sets ssl parameters stat - gets the current system status stmt_init- initializes a statement for use with mysqli_stmt_prepare store_result - transfers a resultset from last query thread_safe - returns whether thread safety is given or not use_result - transfers an unbuffered resultset from last query 属性 affected_rows - gets the number of affected rows in a previous MySQL operation client_info - returns the MySQL client version as a string client_version - returns the MySQL client version as an integer errno - returns the error code for the most recent function call error - returns the error string for the most recent function call field_count - returns the number of columns for the most recent query host_info - returns a string representing the type of connection used info - retrieves information about the most recently executed query insert_id - returns the auto generated id used in the last query protocol_version - returns the version of the MySQL protocol used server_info - returns a string that represents the server version number server_version - returns the version number of the server as an integer sqlstate - returns a string containing the SQLSTATE error code for the last error thread_id - returns the thread ID for the current connection warning_count - returns the number of warnings generated during execution of the previous SQL statement 4. 基本语法 <?php /* Connect to a MySQL server 连接数据库服务器 */ $link = mysqli_connect( 'localhost', /* The host to connect to 连接MySQL地址 */ 'user', /* The user to connect as 连接MySQL用户名 */ 'password', /* The password to use 连接MySQL密码 */ 'world'); /* The default database to query 连接数据库名称*/ if (!$link) { printf("Can't connect to MySQL Server. Errorcode: %s ", mysqli_connect_error()); exit; } /* Send a query to the server 向服务器发送查询请求*/ if ($result = mysqli_query($link, 'SELECT Name, Population FROM City ORDER BY Population DESC LIMIT 5')) { print("Very large cities are: "); /* Fetch the results of the query 返回查询的结果 */ while( $row = mysqli_fetch_assoc($result) ){ printf("%s (%s) ", $row['Name'], $row['Population']); } /* Destroy the result set and free the memory used for it 结束查询释放内存 */ mysqli_free_result($result); } /* Close the connection 关闭连接*/ mysqli_close($link); ?>
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