Ingaba iMySQL ikwenza njani ulandelelwano? Inkcazo yokulandelelana kwedatha ye-MySQL ye-auto-increment

MySQLIndlela yokudala ulandelelwano?MySQL databaseYenza ingxelo yolandelelwano oluzenzekelayo

Ukusetyenziswa kolandelelwano lweMySQL

Ulandelelwano lwe-MySQL luluhlu lwamanani apheleleyo: 1, 2, 3, ..., kuba itafile yedatha inokuba nesitshixo esiphambili sokunyuselwa kwe-auto-indawo, ukuba ufuna ukufezekisa ukongezelelwa kweminye imihlaba, ungasebenzisa i-MySQL. ulandelelwano ukufikelela.

Kwesi sahluko siza kuchaza indlela yokusebenzisa ulandelelwano lweMySQL.

Sebenzisa i-AUTO_INCREMENT

Eyona ndlela ilula yokusebenzisa ulandelelwano kwi-MySQL kukusebenzisa i-MySQL AUTO_INCREMENT ukuchaza iikholamu.

Umzekelo

Itheyibhile yedatha I-Insect yenziwe kumzekelo olandelayo, apho kungekho xabiso lichazwe ngokukhula ngokuzenzekelayo.

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）  
     

  

Fumana AUTO_INCREMENT ixabiso

Kumxhasi we-MySQL ungasebenzisa i-LAST_INSERT_ID () umsebenzi kwi-SQL ukufumana ixabiso loluhlu lokugqibela olonyuswa ngokuzenzekelayo olufakwe kwitafile.

Imisebenzi ehambelanayo nayo inikwe kwi-PHP okanye i-PERL script ukufumana ixabiso lekholomu yokugqibela yokunyusa ngokuzenzekelayo efakwe kwitafile.

Umzekelo wePERL

Sebenzisa ipropathi ye-mysql_insertid ukufumana ixabiso le-AUTO_INCREMENT.Imizekelo yile ilandelayo:

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

Umzekelo we-PHP

I-PHP ifumana ixabiso le-AUTO_INCREMENT ikholamu kwingxelo ephunyeziweyo ye-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 ）;

phinda ulandelelane

Ukuba ucima iirekhodi ezininzi kwitheyibhile yedatha kwaye ufuna ukuhlengahlengisa kwakhona ikholamu ye-AUTO_INCREMENT yedatha eseleyo, unokukwenza ngokucima ikholamu yokunyusa ngokuzenzekelayo uze uyifake kwakhona.Nangona kunjalo, lo msebenzi kufuneka ulumke kakhulu, ukuba kunjalo.Ngexesha elifanayo lokucima, iirekhodi ezintsha zongezwa, kwaye kunokubakho ukuphazamiseka kwedatha. Imisebenzi ihamba ngolu hlobo lulandelayo:

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 ）;
    

Cwangcisa ixabiso lokuqala lolandelelwano

Ngokubanzi, ixabiso lokuqala lolandelelwano ngu-1, kodwa ukuba ufuna ukukhankanya ixabiso lokuqala le-100, ngoko singayenza ngale ngxelo ilandelayo:

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 ; 
    
    
     
    
    

Okanye ungasebenzisa le ngxelo ilandelayo emva kokuba itheyibhile yenziwe ngempumelelo:

mysql > ALTER TABLE t AUTO_INCREMENT = 100 ;