MySQL語法錯誤1064行194添加多對多關係的外鍵

Question

請幫助我。我收到以下消息時，我嘗試運行SQL命令：

 
ERROR 1064 (42000) at line 194: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '(
    ADD CONSTRAINT VFSGRPUSR_REF_VFSGRP 
     FOREIGN KEY (VFSGRP) 
     REFERENCES `VFS' at line 1 

我想實現一個多到多的關係。

 

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DROP TABLE IF EXISTS VFSGRPUSR;
 

CREATE TABLE VFSGRPUSR ( VFSGRP INTEGER REFERENCES VFSGRP(VFSGRP_ID), VFSUSR INTEGER REFERENCES VFSUSR(VFSUSR_ID), PRIMARY KEY (VFSGRP, VFSUSR) )ENGINE=InnoDB DEFAULT CHARSET utf8;
 

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DROP TABLE IF EXISTS VFSUSR;
 

CREATE TABLE VFSUSR ( VFSUSR_ID INTEGER NOT NULL auto_increment, DEPARTMENT INTEGER, FIRSTNAME VARCHAR(255) NOT NULL, SURNAME VARCHAR(255) NOT NULL, LOGIN VARCHAR(255) NOT NULL, PASSWORD BLOB, TOKEN BLOB, PRIMARY KEY (VFSUSR_ID), CONSTRAINT VFSUSR_REF_DEPARTMENT FOREIGN KEY (DEPARTMENT) REFERENCES DEPARTMENT (DEPARTMENT_ID) )ENGINE=InnoDB DEFAULT CHARSET utf8;
 

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DROP TABLE IF EXISTS VFSGRP;
 

CREATE TABLE VFSGRP ( VFSGRP_ID INTEGER NOT NULL auto_increment, GROUPNAME VARCHAR(255) NOT NULL, PRIMARY KEY (VFSGRP_ID) )ENGINE=InnoDB DEFAULT CHARSET utf8;
 

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ALTER TABLE VFSGRPUSR( ADD CONSTRAINT VFSGRPUSR_REF_VFSGRP FOREIGN KEY (VFSGRP) REFERENCES VFSGRP(VFSGRP_ID) )ENGINE=InnoDB DEFAULT CHARSET utf8;
 

ALTER TABLE VFSGRPUSR( ADD CONSTRAINT VFSGRPUSR_REF_VFSUSR FOREIGN KEY (VFSUSR) REFERENCES VFSUSR(VFSUSR_ID) )ENGINE=InnoDB DEFAULT CHARSET utf8; 

Answer 1

爲什麼你想也設置ENGINE和CHARSET？只需使用：

ALTER TABLE VFSGRPUSR 
    ADD CONSTRAINT VFSGRPUSR_REF_VFSGRP 
     FOREIGN KEY (VFSGRP) 
     REFERENCES VFSGRP(VFSGRP_ID); 

，並參考官方文檔可用的語法：http://dev.mysql.com/doc/refman/5.1/en/alter-table.html