


PHP and MYSQL interactive function table study notes_PHP tutorial
Recently I have been studying php(as the current mainstream development language) and MySQL(the best combination with PHP), and I feel that php(as the current mainstream development language) Language)The functions that interact with MySQL(The best combination with PHP) are all procedural. Of course, there are also MySQL(The best combination with PHP)i After writing too much about extensions, object-oriented, Java and C#, I then started writing PHP (as the current mainstream development language) . I felt a little uncomfortable and felt like I was back to the age of learning C. I learned some functions today and recorded them so that I can refer to them when I forget them in the future.
Description | Function name | Function details | Function description |
Establish a database connection | MySQL(The best combination with PHP)_connect() | resource MySQL(The best combination with PHP)_connect([string hostname [:port] [:/path/to/socket] [, string username] [, string password]]) Example :$conn = @MySQL(The best combination with PHP)_connect("localhost", "username", "password") or dir("Cannot connect to MySQL(With PHP) The best combination) Server"); |
Use the connection that must be displayed to close the connection |
Establish a database connection | MySQL(The best combination with PHP)_pconnect() | resource MySQL(The best combination with PHP)_pconnect([string hostname [:port] [:/path/to/socket] [, string username] [, string password ]]) Example: $conn = @MySQL(The best combination with PHP)_pconnect("localhost", "username", "password") or dir("Cannot connect to MySQL (The best combination with PHP) Server"); |
Using this connection function does not require closing the connection explicitly, it is equivalent to using a connection pool |
Close database connection | MySQL(The best combination with PHP)_close() | $conn = @MySQL(The best combination with PHP)_connect("localhost", "username", "password") or die("Cannot connect to MySQL(With PHP The best combination) Server"); @MySQL(The best combination with PHP)_select_db("MyDatabase") or die("This database cannot be selected, or the database is not Exists"); echo "You have connected to the MyDatabase database"; MySQL(The best combination with PHP)_close(); |
|
Select database | MySQL(The best combination with PHP)_select_db() | boolean MySQL(The best combination with PHP)_select_db(string db_name [, resource link_id]) $conn = @MySQL(The best combination with PHP) _connect("localhost", "username", "password") or die("Cannot connect to MySQL(The best combination with PHP) Server"); @MySQL(The best combination with PHP)_select_db("MyDatabase") or die("This database cannot be selected, or the database does not exist"); |

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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