


We often encounter the need to export data from the database to Excel files. It is indeed easier to use some open source libraries, such as PHPExcel, but the support for large amounts of data is very poor and it is easy to reach the PHP memory. Usage limit. The method here is to use fputcsv to write CSV files and directly output Excel files to the browser.
// 输出Excel文件头,可把user.csv换成你要的文件名 header('Content-Type: application/vnd.ms-excel'); header('Content-Disposition: attachment;filename="user.csv"'); header('Cache-Control: max-age=0'); // 从数据库中获取数据,为了节省内存,不要把数据一次性读到内存,从句柄中一行一行读即可 $sql = 'select * from tbl where ……'; $stmt = $db->query($sql); // 打开PHP文件句柄,php://output 表示直接输出到浏览器 $fp = fopen('php://output', 'a'); // 输出Excel列名信息 $head = array('姓名', '性别', '年龄', 'Email', '电话', '……'); foreach ($head as $i => $v) { // CSV的Excel支持GBK编码,一定要转换,否则乱码 $head[$i] = iconv('utf-8', 'gbk', $v); } // 将数据通过fputcsv写到文件句柄 fputcsv($fp, $head); // 计数器 $cnt = 0; // 每隔$limit行,刷新一下输出buffer,不要太大,也不要太小 $limit = 100000; // 逐行取出数据,不浪费内存 while ($row = $stmt->fetch(Zend_Db::FETCH_NUM)) { $cnt ++; if ($limit == $cnt) { //刷新一下输出buffer,防止由于数据过多造成问题 ob_flush(); flush(); $cnt = 0; } foreach ($row as $i => $v) { $row[$i] = iconv('utf-8', 'gbk', $v); } fputcsv($fp, $row); }
Easy to use, very memory-saving, and does not rely on third-party libraries.

Thedifferencebetweenunset()andsession_destroy()isthatunset()clearsspecificsessionvariableswhilekeepingthesessionactive,whereassession_destroy()terminatestheentiresession.1)Useunset()toremovespecificsessionvariableswithoutaffectingthesession'soveralls

Stickysessionsensureuserrequestsareroutedtothesameserverforsessiondataconsistency.1)SessionIdentificationassignsuserstoserversusingcookiesorURLmodifications.2)ConsistentRoutingdirectssubsequentrequeststothesameserver.3)LoadBalancingdistributesnewuser

PHPoffersvarioussessionsavehandlers:1)Files:Default,simplebutmaybottleneckonhigh-trafficsites.2)Memcached:High-performance,idealforspeed-criticalapplications.3)Redis:SimilartoMemcached,withaddedpersistence.4)Databases:Offerscontrol,usefulforintegrati

Session in PHP is a mechanism for saving user data on the server side to maintain state between multiple requests. Specifically, 1) the session is started by the session_start() function, and data is stored and read through the $_SESSION super global array; 2) the session data is stored in the server's temporary files by default, but can be optimized through database or memory storage; 3) the session can be used to realize user login status tracking and shopping cart management functions; 4) Pay attention to the secure transmission and performance optimization of the session to ensure the security and efficiency of the application.

PHPsessionsstartwithsession_start(),whichgeneratesauniqueIDandcreatesaserverfile;theypersistacrossrequestsandcanbemanuallyendedwithsession_destroy().1)Sessionsbeginwhensession_start()iscalled,creatingauniqueIDandserverfile.2)Theycontinueasdataisloade

Absolute session timeout starts at the time of session creation, while an idle session timeout starts at the time of user's no operation. Absolute session timeout is suitable for scenarios where strict control of the session life cycle is required, such as financial applications; idle session timeout is suitable for applications that want users to keep their session active for a long time, such as social media.

The server session failure can be solved through the following steps: 1. Check the server configuration to ensure that the session is set correctly. 2. Verify client cookies, confirm that the browser supports it and send it correctly. 3. Check session storage services, such as Redis, to ensure that they are running normally. 4. Review the application code to ensure the correct session logic. Through these steps, conversation problems can be effectively diagnosed and repaired and user experience can be improved.

session_start()iscrucialinPHPformanagingusersessions.1)Itinitiatesanewsessionifnoneexists,2)resumesanexistingsession,and3)setsasessioncookieforcontinuityacrossrequests,enablingapplicationslikeuserauthenticationandpersonalizedcontent.


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