PHP+MYSQL查询数据库导致系统很卡!
PHP代码:
<br> nbsp;html><!--STATUS OK--> <br> <meta><br> <br> <style><br /> table,td{border:1px solid #ccc;}<br /> td{padding:10px}<br /> <br /> </style><br> <br> <br> <br> <?php <br /> $dbh = @mysql_connect("localhost:3306","root","123456");<br> <br> /* 定义变量dbh , mysql_connect()函数的意思是连接mysql数据库, "@"的意思是屏蔽报错 */<br> if(!$dbh){die("error");}<br> /* die()函数的意思是将括号里的字串送到浏览器并中断php程式 (script)。括号里的参数为欲送出的字串。 */<br> @mysql_select_db("data", $dbh);<br> <br> mysql_query("SET NAMES data");<br> <br> <br> <br> ?><br> <br> <br><br><br><br> <br> <center> <br> <form> <br> <input><br> <input><br> <input><br> <span><br> <input></span> </form> <br> <br> </center><br> <br> <br> $wd=$_POST["wd"];<br> /* 选择mysql服务器里的一个数据库,这里选的数据库名为 ok */<br> $q = "(select * from tabal where user like '$wd%' or email LIKE '$wd%')<br> union all<br> (select * from tabal1 where user like '$wd%' or email LIKE '$wd%')<br> union all<br> (select * from tabal2 where user like '$wd%' or email LIKE '$wd%')<br> union all<br> (select * from tabal3 where user like '$wd%' or email LIKE '$wd%')<br> union all<br> (select * from tabal4 where user like '$wd%' or email LIKE '$wd%')<br> union all<br> (select * from tabal5 where user like '$wd%' or email LIKE '$wd%')<br> union all<br> (select * from tabal6 where user like '$wd%' or email LIKE '$wd%')<br> union all<br> (select * from tabal7 where user like '$wd%' or email LIKE '$wd%')<br> union all<br> (select * from tabal8 where user like '$wd%' or email LIKE '$wd%')<br> union all<br> (select * from tabal9 where user like '$wd%' or email LIKE '$wd%')<br> union all<br> (select * from tabal10 where email LIKE '$wd%')<br> union all<br> (select * from tabal11 where user like '$wd%' or email LIKE '$wd%') LIMIT 0,20";<br> <br> /* 定义变量q, "select * from abc"是一个sql语句,意思是读取表abc中的数据 */<br> ?><br> <br><br> <br> <center> <br> <table> <br> <br> <br> $rs = mysql_query($q, $dbh);<br> <br> while($row = mysql_fetch_array($rs))<br> <br> echo "<tr> <td>$row[user]</td> <td>$row[pass]</td> <td>$row[email]</td> </tr> ";<br> <br> ?><br> <br> </table> <br> <br> </center><br> <br> <br> @mysql_close($dbh); <div class="clear"> </div>

ThesecrettokeepingaPHP-poweredwebsiterunningsmoothlyunderheavyloadinvolvesseveralkeystrategies:1)ImplementopcodecachingwithOPcachetoreducescriptexecutiontime,2)UsedatabasequerycachingwithRedistolessendatabaseload,3)LeverageCDNslikeCloudflareforservin

You should care about DependencyInjection(DI) because it makes your code clearer and easier to maintain. 1) DI makes it more modular by decoupling classes, 2) improves the convenience of testing and code flexibility, 3) Use DI containers to manage complex dependencies, but pay attention to performance impact and circular dependencies, 4) The best practice is to rely on abstract interfaces to achieve loose coupling.

Yes,optimizingaPHPapplicationispossibleandessential.1)ImplementcachingusingAPCutoreducedatabaseload.2)Optimizedatabaseswithindexing,efficientqueries,andconnectionpooling.3)Enhancecodewithbuilt-infunctions,avoidingglobalvariables,andusingopcodecaching

ThekeystrategiestosignificantlyboostPHPapplicationperformanceare:1)UseopcodecachinglikeOPcachetoreduceexecutiontime,2)Optimizedatabaseinteractionswithpreparedstatementsandproperindexing,3)ConfigurewebserverslikeNginxwithPHP-FPMforbetterperformance,4)

APHPDependencyInjectionContainerisatoolthatmanagesclassdependencies,enhancingcodemodularity,testability,andmaintainability.Itactsasacentralhubforcreatingandinjectingdependencies,thusreducingtightcouplingandeasingunittesting.

Select DependencyInjection (DI) for large applications, ServiceLocator is suitable for small projects or prototypes. 1) DI improves the testability and modularity of the code through constructor injection. 2) ServiceLocator obtains services through center registration, which is convenient but may lead to an increase in code coupling.

PHPapplicationscanbeoptimizedforspeedandefficiencyby:1)enablingopcacheinphp.ini,2)usingpreparedstatementswithPDOfordatabasequeries,3)replacingloopswitharray_filterandarray_mapfordataprocessing,4)configuringNginxasareverseproxy,5)implementingcachingwi

PHPemailvalidationinvolvesthreesteps:1)Formatvalidationusingregularexpressionstochecktheemailformat;2)DNSvalidationtoensurethedomainhasavalidMXrecord;3)SMTPvalidation,themostthoroughmethod,whichchecksifthemailboxexistsbyconnectingtotheSMTPserver.Impl


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