MySQL inogadzira sei kutevedzana? MySQL dhatabhesi kugadzira otomatiki-kuwedzera kutevedzana chirevo

MySQLNzira yekugadzira sei kutevedzana?MySQL databaseGadzira auto-incrementing sequence statement

MySQL sequence kushandiswa

MySQL sequence is set of integers: 1, 2, 3, ..., sezvo tafura yedata inogona kungova nemunda mumwe chete auto-increment primary kiyi, kana iwe uchida kuwana otomatiki kuwedzera kwemamwe minda, unogona kushandisa MySQL kutevedzana ku. achieve.

Muchitsauko chino tichatsanangura nzira yekushandisa MySQL sequences.

Shandisa AUTO_INCREMENT

Nzira iri nyore yekushandisa kutevedzana muMySQL ndeye kushandisa MySQL AUTO_INCREMENT kutsanangura makoramu.

muenzaniso

Iyo data tafura Insect inogadzirwa mumuenzaniso unotevera, umo pasina kukosha kunotsanangurwa kuti uwane otomatiki kukura.

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）  
     

  

Wana AUTO_INCREMENT kukosha

Mumutengi weMySQL unogona kushandisa LAST_INSERT_ID() basa muSQL kuti uwane kukosha kweiyo yekupedzisira-yakawedzerwa mbiru inoiswa mutafura.

Mabasa anoenderana anopihwawo muiyo PHP kana PERL script kuti uwane kukosha kweyekupedzisira auto-increment column inoiswa mutafura.

PERL muenzaniso

Shandisa mysql_insertid pfuma kuti uwane kukosha kweAUTO_INCREMENT.Mienzaniso ndeiyi inotevera:

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

PHP muenzaniso

PHP inowana kukosha kweiyo AUTO_INCREMENT koramu mune yakatemerwa isa SQL statement kuburikidza ne mysql_insert_id() basa.

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 ）;

reset kutevedzana

Kana iwe ukadzima akawanda marekodhi mutafura yedata uye uchida kugadzirisa zvakare AUTO_INCREMENT column yedata rasara, unogona kuzviita nekudzima auto-incrementing column wobva wawedzera zvakare.Nekudaro, kuvhiya uku kunofanirwa kungwarira zvakanyanya, kana zvachose.Panguva imwe chete yekudzimwa, zvinyorwa zvitsva zvinowedzerwa, uye panogona kunge paine kuvhiringidzika kwedata.

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 ）;
    

Isa kukosha kwekutanga kwekutevedzana

Kazhinji, kukosha kwekutanga kwekutevedzana ndeye 1, asi kana iwe uchida kutsanangura kukosha kwekutanga kwe100, tinogona kuzviita nechirevo chinotevera:

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 ; 
    
    
     
    
    

Kana iwe unogona zvakare kushandisa chirevo chinotevera mushure mekunge tafura yagadzirwa zvinobudirira:

mysql > ALTER TABLE t AUTO_INCREMENT = 100 ;