<?php /* MYSQL 数据库访问封装类 MYSQL 数据访问方式,php4支持以mysql_开头的过程访问方式,php5开始支持以mysqli_开头的过程和mysqli面向对象 访问方式,本封装类以mysql_封装 数据访问的一般流程: 1,连接数据库 mysql_connect or mysql_pconnect 2,选择数据库 mysql_select_db 3,执行SQL查询 mysql_query 4,处理返回的数据 mysql_fetch_array mysql_num_rows mysql_fetch_assoc mysql_fetch_row etc */ class db_mysql { var $querynum = 0 ; //当前页面进程查询数据库的次数 var $dblink ; //数据库连接资源 //链接数据库 function connect($dbhost,$dbuser,$dbpw,$dbname='',$dbcharset='utf-8',$pconnect=0 , $halt=true) { $func = empty($pconnect) ? 'mysql_connect' : 'mysql_pconnect' ; $this->dblink = @$func($dbhost,$dbuser,$dbpw) ; if ($halt && !$this->dblink) { $this->halt("无法链接数据库!"); } //设置查询字符集 mysql_query("SET character_set_connection={$dbcharset},character_set_results={$dbcharset},character_set_client=binary",$this->dblink) ; //选择数据库 $dbname && @mysql_select_db($dbname,$this->dblink) ; } //选择数据库 function select_db($dbname) { return mysql_select_db($dbname,$this->dblink); } //执行SQL查询 function query($sql) { $this->querynum++ ; return mysql_query($sql,$this->dblink) ; } //返回最近一次与连接句柄关联的INSERT,UPDATE 或DELETE 查询所影响的记录行数 function affected_rows() { return mysql_affected_rows($this->dblink) ; } //取得结果集中行的数目,只对select查询的结果集有效 function num_rows($result) { return mysql_num_rows($result) ; } //获得单格的查询结果 function result($result,$row=0) { return mysql_result($result,$row) ; } //取得上一步 INSERT 操作产生的 ID,只对表有AUTO_INCREMENT ID的操作有效 function insert_id() { return ($id = mysql_insert_id($this->dblink)) >= 0 ? $id : $this->result($this->query("SELECT last_insert_id()"), 0); } //从结果集提取当前行,以数字为key表示的关联数组形式返回 function fetch_row($result) { return mysql_fetch_row($result) ; } //从结果集提取当前行,以字段名为key表示的关联数组形式返回 function fetch_assoc($result) { return mysql_fetch_assoc($result); } //从结果集提取当前行,以字段名和数字为key表示的关联数组形式返回 function fetch_array($result) { return mysql_fetch_array($result); } //关闭链接 function close() { return mysql_close($this->dblink) ; } //输出简单的错误html提示信息并终止程序 function halt($msg) { $message = "<html>\n<head>\n" ; $message .= "<meta content='text/html;charset=gb2312'>\n" ; $message .= "</head>\n" ; $message .= "<body>\n" ; $message .= "数据库出错:".htmlspecialchars($msg)."\n" ; $message .= "</body>\n" ; $message .= "</html>" ; echo $message ; exit ; } } ?>

What’s still popular is the ease of use, flexibility and a strong ecosystem. 1) Ease of use and simple syntax make it the first choice for beginners. 2) Closely integrated with web development, excellent interaction with HTTP requests and database. 3) The huge ecosystem provides a wealth of tools and libraries. 4) Active community and open source nature adapts them to new needs and technology trends.

PHP and Python are both high-level programming languages that are widely used in web development, data processing and automation tasks. 1.PHP is often used to build dynamic websites and content management systems, while Python is often used to build web frameworks and data science. 2.PHP uses echo to output content, Python uses print. 3. Both support object-oriented programming, but the syntax and keywords are different. 4. PHP supports weak type conversion, while Python is more stringent. 5. PHP performance optimization includes using OPcache and asynchronous programming, while Python uses cProfile and asynchronous programming.

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.

PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.

PHP remains important in the modernization process because it supports a large number of websites and applications and adapts to development needs through frameworks. 1.PHP7 improves performance and introduces new features. 2. Modern frameworks such as Laravel, Symfony and CodeIgniter simplify development and improve code quality. 3. Performance optimization and best practices further improve application efficiency.

PHPhassignificantlyimpactedwebdevelopmentandextendsbeyondit.1)ItpowersmajorplatformslikeWordPressandexcelsindatabaseinteractions.2)PHP'sadaptabilityallowsittoscaleforlargeapplicationsusingframeworkslikeLaravel.3)Beyondweb,PHPisusedincommand-linescrip

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values and handle functions that may return null values.


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