I-MySQL ikwenza kanjani ukulandelana? Isitatimende sokulandelana sokukhula kwesizindalwazi se-MySQL

MySQLIndlela yokudala ukulandelana?MySQL databaseDala isitatimende sokulandelana esikhuphuka ngokuzenzakalela

Ukusetshenziswa kokulandelana kwe-MySQL

Ukulandelana kwe-MySQL isethi yama-integers: 1, 2, 3, ..., njengoba ithebula ledatha lingaba nokhiye owodwa oyinhloko wokwandisa inkambu ngokuzenzakalela, uma ufuna ukuzuza ukukhuphuka okuzenzakalelayo kwezinye izinkambu, ungasebenzisa ukulandelana kwe-MySQL ukuze zuza.

Kulesi sahluko sizochaza indlela yokusebenzisa ukulandelana kwe-MySQL.

Sebenzisa i-AUTO_INCREMENT

Indlela elula yokusebenzisa ukulandelana ku-MySQL ukusebenzisa i-MySQL AUTO_INCREMENT ukuchaza amakholomu.

Isibonelo

Ithebula ledatha I-Insect idalwe esibonelweni esilandelayo, lapho lingekho inani elishiwo ekukhuleni okuzenzakalelayo.

mysql > CREATE TABLE昆虫
     - > （- > id INT UNSIGNED NOT NULL AUTO_INCREMENT ，- > PRIMARY KEY （id ），- > name VARCHAR （30 ）NOT NULL ，＃昆虫类型- > 日期DATE NOT NULL ，＃收集日期- > origin VARCHAR （30 ）NOT NULL ＃where collected ）; 查询OK ，0 行受影响（0.02 秒）
mysql > 
    
    
     
     
    

 INSERT INTO insects （id ，name ，date ，origin ）VALUES
     - > （NULL ，'housefly' ，'2001-09-10' ，'kitchen' ），- > （NULL ，'millipede' ，'2001-09-10 ' ，'车道' ），- > （NULL ，'grasshopper' ，'2001-09-10' ，'front yard' ）; 查询OK ， 
     
     
 秒）记录：3 重复：0 警告：0 
mysql > 选择* 从昆虫ORDER BY ID ; + ---- + ------------- + ------------ + ------------ + | id | 名字         | 日期        | 起源      | + ---- + ------------- + ------------ + ------------ + | 1 | 家蝇     | 2001 - 09 - 10 | 厨房     | | 2 | 千足虫   
       



     
   | 2001 - 09 - 10 | 车道    | | 3 | 蚱蜢| 2001 - 09 - 10 | 前院| + ---- + ------------- + ------------ + ------------ + 3 行中集（0.00 秒）  
     

  

Thola inani elingu-AUTO_INCREMENT

Kuklayenti le-MySQL ungasebenzisa umsebenzi we-LAST_INSERT_ID() ku-SQL ukuze uthole inani lekholomu yokugcina ekhushulelwe ngokuzenzakalela lifakwe kuthebula.

Imisebenzi ehambisanayo iphinde ihlinzekwe kusikripthi se-PHP noma se-PERL ukuze kutholwe inani lekholomu yokugcina yokwengeza ngokuzenzakalela efakwe kuthebula.

Isibonelo se-PERL

Sebenzisa isakhiwo se-mysql_insertid ukuze uthole inani elingu-AUTO_INCREMENT.Izibonelo zimi kanje:

$ dbh - > do （“INSERT INTO insect（name，date，origin） 
VALUES（'moth'，'2001-09-14'，'windowsill'）“ ）; my $ seq = $ dbh - > { mysql_insertid };

Isibonelo se-PHP

I-PHP ithola inani lekholomu ethi AUTO_INCREMENT esitatimendeni esifakiwe se-SQL ngomsebenzi we-mysql_insert_id().

mysql_query （“INSERT INTO昆虫（名字，日期，起源）
VALUES（'moth'，'2001-09-14'，'windowsill'）“ ，$ conn_id ）; 
$ seq = mysql_insert_id （$ conn_id ）;

setha kabusha ukulandelana

Uma ususa amarekhodi amaningi kuthebula ledatha futhi ufuna ukuhlela kabusha ikholomu engu-AUTO_INCREMENT yedatha esele, ungenza kanjalo ngokususa ikholomu yokukhulisa ngokuzenzakalela bese uyengeza futhi.Nokho, lo msebenzi kufanele uqaphele kakhulu, uma kukhona.Ngesikhathi esifanayo sokususwa, amarekhodi amasha ayengezwa, futhi kungase kube nokudideka kwedatha. Imisebenzi imi kanje:

mysql > ALTER TABLE昆虫DROP ID ; 
mysql > ALTER TABLE昆虫
     - > ADD ID INT UNSIGNED NOT NULL AUTO_INCREMENT FIRST ，- > ADD PRIMARY KEY （id ）;
    

Setha inani lokuqala lokulandelana

Ngokuvamile, inani lokuqala lokulandelana ngu-1, kodwa uma udinga ukucacisa inani lokuqala lika-100, khona-ke singakwenza ngesitatimende esilandelayo:

mysql > CREATE TABLE昆虫
     - > （- > id INT UNSIGNED NOT NULL AUTO_INCREMENT ，- > PRIMARY KEY （id ），- > name VARCHAR （30 ）NOT NULL ，- > date DATE NOT NULL ，- > origin VARCHAR （30 ）NOT NULL
 ）engine = innodb auto_increment = 100 charset = utf8 ; 
    
    
     
    
    

Noma ungasebenzisa isitatimende esilandelayo ngemuva kokuthi ithebula lidalwe ngempumelelo:

mysql > ALTER TABLE t AUTO_INCREMENT = 100 ;