php操作类
<?php /**+---------------------- * Mysql操作类+---------------------- * 文件名称 Db.class.php+---------------------- * 文件描述 mysql操作类+---------------------- */class Db{ //数据库连接标识 protected $link = null; //当前操作的表 public $table = ''; //查询参数 protected $options = array(); //当前执行的SQL语句 protected $sql = ''; //用什么编码传递数据 protected $dbCharset = 'utf8'; //缓存路径 protected $cachePath = './cache/'; //缓存扩展名 protected $cacheFileExt = "php"; //缓存文件名 protected $cacheFileName; //是否缓存 protected $cache = false; //缓存更新时间秒数 protected $cacheLimitTime = 60; //数据返回类型, 1代表数组, 2代表对象 protected $returnType = 1; /* * 根据当前动态文件生成缓存文件名 */ function setCacheFileName($fileName) { $cacheFileName = $this->cachePath . strtoupper(md5($fileName)).".".$this->cacheFileExt; $this->cacheFileName=$cacheFileName; } /* * 根据当前动态文件生成缓存文件名 */ function getCacheFileName() { return $this->cacheFileName; } /** * 连接数据库 * * @access public * @param array $db 数据库配置 * @return resource 数据库连接标识 */ public function connect($db){ //根据配置使用不同函数连接数据库 $db['host'] = isset($db['port']) ? $db['host'].':'.$db['port']: $db['host']; $db['char'] = isset($db['char']) ? $db['char']: $this->dbCharset; $func = $db['pconnect'] ? 'mysql_pconnect' : 'mysql_connect'; $this->link = $func($db['host'], $db['user'], $db['pwd']); mysql_select_db($db['database'], $this->link); mysql_query("SET NAMES '{$db['char']}'"); $this->cachePath = isset($db['cachepath']) ? $db['cachepath']: $this->cachePath; return $this->link; } /** * 查询符合条件的一条记录 * * @access public * @param string $where 查询条件 * @param string $field 查询字段 * @param string $table 表 * @return mixed 符合条件的记录 */ public function find($where = NULL, $field = '*', $table = ''){ return $this->findAll($where = NULL, $field = '*', $table = '', FALSE); } /** * 查询符合条件的所有记录 * * @access public * @param string $where 查询条件 * @param string $field 查询字段 * @param string $table 表 * @return mixed 符合条件的记录 */ public function findAll($where = NULL, $field = '*', $table = '', $all = TRUE){ $this->options['where'] = is_null($where) ? @$this->options['where']: $where; $this->options['field'] = isset($this->options['field']) ? $this->options['field']: $field; $this->options['table'] = $table == '' ? $this->table: $table; $sql = "SELECT {$this->options['field']} FROM `{$this->options['table']}` "; $sql .= isset($this->options['join']) ? ' LEFT JOIN '.$this->options['join']: ''; $sql .= isset($this->options['where']) ? ' WHERE '.$this->options['where']: ''; $sql .= isset($this->options['group']) ? ' GROUP BY '.$this->options['group']: ''; $sql .= isset($this->options['having']) ? ' HAVING '.$this->options['having']: ''; $sql .= isset($this->options['order']) ? ' ORDER BY '.$this->options['order']: ''; $sql .= isset($this->options['limit']) ? ' LIMIT '.$this->options['limit']: ''; $this->sql = $sql; $row = NULL; //如果开启了缓存, 那么重缓存中获取数据 if ($this->cache === TRUE){ $this->setCacheFileName($this->sql); $row = $this->readCache(); } //如果读取失败, 或则没有开启缓存 if (is_null($row)){ $result = $this->query(); $row = $all === TRUE ? $this->fetchAll($result): $this->fetch($result); //如果开启了缓存, 那么就写入 if ($this->cache === TRUE){ $this->writeCache($row); } $this->options = array(); } return $row; } /** * 读取结果集中的所有记录到数组中 * * @access public * @param resource $result 结果集 * @return array */ public function fetchAll($result = NULL){ $rows = array(); while ($row = $this->fetch($result)){ $rows[] = $row; } return $rows; } /** * 读取结果集中的一行记录到数组中 * * @access public * @param resource $result 结果集 * @param int $type 返回类型, 1为数组, 2为对象 * @return mixed 根据返回类型返回 */ public function fetch($result = NULL, $type = NULL){ $result = is_null($result) ? $this->result: $result; $type = is_null($type) ? $this->returnType: $type; $func = $type === 1 ? 'mysql_fetch_assoc' : 'mysql_fetch_object'; return $func($result); } /** * 执行SQL命令 * * @access public * @param string $sql SQL命令 * @param resource $link 数据库连接标识 * @return mixed 数据库结果集 */ public function query($sql = '', $link = NULL){ $sql = empty($sql) ? $this->sql: $sql; $link = is_null($link) ? $this->link: $link; $this->result = mysql_query($sql, $link); if (is_resource($this->result)){ return $this->result; } //如果执行SQL出现错误, 那么抛出异常 exit('<strong>Mysql error:</strong>'.$this->getError()); } /** * 执行SQL命令 * * @access public * @param string $sql SQL命令 * @param resource $link 数据库连接标识 * @return bool 是否执行成功 */ public function execute($sql = '', $link = NULL){ $sql = empty($sql) ? $this->sql: $sql; $link = is_null($link) ? $this->link: $link; if (mysql_query($sql, $link)){ return TRUE; } return FALSE; } /** * 插入记录 * * @access public * @param array $data 插入的记录, 格式:array('字段名'=>'值', '字段名'=>'值'); * @param string $table 表名 * @return bool 当前记录id */ public function add($data, $table = NULL){ $table = is_null($table) ? $this->table: $table; $sql = "INSERT INTO `{$table}`"; $fields = $values = array(); $field = $value = ''; //遍历记录, 格式化字段名称与值 foreach($data as $key => $val){ $fields[] = "`{$table}`.`{$key}`"; $values[] = is_numeric($val) ? $val : "'{$val}'"; } $field = join(',', $fields); $value = join(',', $values); unset($fields, $values); $sql .= "({$field}) VALUES({$value})"; $this->sql = $sql; $this->execute(); return $this->insertId(); } /** * 删除记录 * * @access public * @param string $where 条件 * @param string $table 表名 * @return bool 影响行数 */ public function delete($where = NULL, $table = NULL){ $table = is_null($table) ? $this->table: $table; $where = is_null($where) ? @$this->options['where']: $where; $sql = "DELETE FROM `{$table}` WHERE {$where}"; $this->sql = $sql; $this->execute(); return $this->affectedRows(); } /** * 更新记录 * * @access public * @param array $data 更新的数据 格式:array('字段名' => 值); * @param string $where 更新条件 * @param string $table 表名 * @return bool 影响多少条信息 */ public function update($data, $where = NULL, $table = NULL){ $table = is_null($table) ? $this->table: $table; $where = is_null($where) ? @$this->options['where']: $where; $sql = "UPDATE `{$table}` SET "; $values = array(); foreach($data as $key => $val){ $val = is_numeric($val) ? $val : "'{$val}'"; $values[] = "`{$table}`.`{$key}` = {$val}"; } $value = join(',', $values); $this->sql = $sql.$value." WHERE {$where}"; $this->execute(); return $this->affectedRows(); } /** * 读取缓存 * * @access public * @return mixed 如果读取成功返回缓存内容, 否则返回NULL */ protected function readCache(){ $file = $this->getCacheFileName(); if (file_exists($file)){ //缓存过期 if ((filemtime($file) + $this->cacheLimitTime) returnType){ $row = include $file; } else{ $data = file_get_contents($file); $row = unserialize($data); } return $row; } return NULL; } /** * 写入缓存 * * @access public * @param mixed $data 缓存内容 * @return bool 是否写入成功 */ public function writeCache($data){ $file = $this->getCacheFileName(); if ($this->makeDir(dirname($file))){ if (1 === $this->returnType){ $data = '<?php return '.var_export($data, TRUE).';?>'; }else{ $data = serialize($data); } } return file_put_contents($file, $data); } /* * 清除缓存文件 * string $fileName 指定文件名(含函数)或者all(全部) * 返回:清除成功返回true,反之返回false */ function clearCache( $fileName = "all" ) { if( $fileName != "all" ) { if( file_exists( $fileName ) ) { return @unlink( $fileName ); }else return false; } if ( is_dir( $this->cachePath ) ) { if ( $dir = @opendir( $this->cachePath ) ) { while ( $file = @readdir( $dir ) ) { $check = is_dir( $file ); if ( !$check ) @unlink( $this->cachePath . $file ); } @closedir( $dir ); return true; }else{ return false; } }else{ return false; } } /* * 连续建目录 * string $dir 目录字符串 * int $mode 权限数字 * 返回:顺利创建或者全部已建返回true,其它方式返回false */ function makeDir( $dir, $mode = "0777" ) { if( ! $dir ) return 0; $dir = str_replace( "\\", "/", $dir ); $mdir = ""; foreach( explode( "/", $dir ) as $val ) { $mdir .= $val."/"; if( $val == ".." || $val == "." || trim( $val ) == "" ) continue; if( ! file_exists( $mdir ) ) { if([email protected]( $mdir, $mode )){ return false; } } } return true; } //自动加载函数, 实现特殊操作 public function __call($func, $args) { if(in_array($func, array('field', 'join', 'where', 'order', 'group', 'limit', 'having'))) { $this->options[$func] = array_shift($args); return $this; } elseif($func === 'table'){ $this->options['table'] = array_shift($args); $this->table = $this->options['table']; return $this; } //如果函数不存在, 则抛出异常 exit('Call to undefined method Db::' . $func . '()'); }//------------------------------------------- //返回上一次操作所影响的行数 public function affectedRows($link = null){ $link = is_null($link) ? $this->link : $link; return mysql_affected_rows($link); } //返回上一次操作记录的id public function insertId($link = null){ $link = is_null($link) ? $this->link : $link; return mysql_insert_id($link); } //清空结果集 public function free($result = null){ $result = is_null($result) ? $this->result : $result; return mysql_free_result($result); } //返回错误信息 public function getError($link = NULL){ $link = is_null($link) ? $this->link : $link; return mysql_error($link); } //返回错误编号 public function getErrno($link = NULL){ $link = is_null($link) ? $this->link : $link; return mysql_errno($link); }}?>

PHPsessionstrackuserdataacrossmultiplepagerequestsusingauniqueIDstoredinacookie.Here'showtomanagethemeffectively:1)Startasessionwithsession_start()andstoredatain$_SESSION.2)RegeneratethesessionIDafterloginwithsession_regenerate_id(true)topreventsessi

In PHP, iterating through session data can be achieved through the following steps: 1. Start the session using session_start(). 2. Iterate through foreach loop through all key-value pairs in the $_SESSION array. 3. When processing complex data structures, use is_array() or is_object() functions and use print_r() to output detailed information. 4. When optimizing traversal, paging can be used to avoid processing large amounts of data at one time. This will help you manage and use PHP session data more efficiently in your actual project.

The session realizes user authentication through the server-side state management mechanism. 1) Session creation and generation of unique IDs, 2) IDs are passed through cookies, 3) Server stores and accesses session data through IDs, 4) User authentication and status management are realized, improving application security and user experience.

Tostoreauser'snameinaPHPsession,startthesessionwithsession_start(),thenassignthenameto$_SESSION['username'].1)Usesession_start()toinitializethesession.2)Assigntheuser'snameto$_SESSION['username'].Thisallowsyoutoaccessthenameacrossmultiplepages,enhanc

Reasons for PHPSession failure include configuration errors, cookie issues, and session expiration. 1. Configuration error: Check and set the correct session.save_path. 2.Cookie problem: Make sure the cookie is set correctly. 3.Session expires: Adjust session.gc_maxlifetime value to extend session time.

Methods to debug session problems in PHP include: 1. Check whether the session is started correctly; 2. Verify the delivery of the session ID; 3. Check the storage and reading of session data; 4. Check the server configuration. By outputting session ID and data, viewing session file content, etc., you can effectively diagnose and solve session-related problems.

Multiple calls to session_start() will result in warning messages and possible data overwrites. 1) PHP will issue a warning, prompting that the session has been started. 2) It may cause unexpected overwriting of session data. 3) Use session_status() to check the session status to avoid repeated calls.

Configuring the session lifecycle in PHP can be achieved by setting session.gc_maxlifetime and session.cookie_lifetime. 1) session.gc_maxlifetime controls the survival time of server-side session data, 2) session.cookie_lifetime controls the life cycle of client cookies. When set to 0, the cookie expires when the browser is closed.


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