[英]MySQL Primary Key as Foreign Key - Constraint error
假设我有3个表。
CREATE TABLE IF NOT EXISTS GROUP (
ID_GROUP INT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
GROUP VARCHAR(50) NOT NULL,
INDEX(GROUP)
) ENGINE=INNODB DEFAULT CHARACTER SET = utf8 COLLATE = utf8_general_ci;)
CREATE TABLE IF NOT EXISTS USERZ (
ID CHAR(8) NOT NULL,
GROUP VARCHAR(50) NOT NULL,
FIRST_NAME VARCHAR(100) NULL DEFAULT NULL ,
LAST_NAME VARCHAR(100) NULL DEFAULT NULL,
DATE_CREATED TIMESTAMP NULL DEFAULT CURRENT_TIMESTAMP,
PASSWORD VARCHAR(8) NULL DEFAULT 'HELLOWORLD',
PRIMARY KEY (ID),
INDEX (ID),
INDEX (GROUP),
FOREIGN KEY (GROUP) REFERENCES GROUP (GROUP)
) ENGINE=INNODB DEFAULT CHARACTER SET = utf8 COLLATE = utf8_general_ci;)
CREATE TABLE IF NOT EXISTS WORKERS (
ID CHAR(8) NOT NULL PRIMARY KEY,
DATE_START TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
DATE_END TIMESTAMP NULL,
FOREIGN KEY (ID) REFERENCES USERZ (ID)
) ENGINE=INNODB DEFAULT CHARACTER SET = utf8 COLLATE = utf8_general_ci;)
我在表USERZ中插入数据没有问题。 但是当涉及到向表WORKERS添加记录时,我得到了错误消息:
mysql.connector.errors.IntegrityError:1452(23000):不能添加或更新子行,外键约束失败( DATABASENAME
。 WORKERS
,约束WORKERS_ibfk_1
外键( ID
)参考文献USERZ
( ID
))
我肯定知道这与WORKERS主键(ID)有关,是指USERZ(ID)。 即使我知道USERZ ID中存在USERZ ID,也不会允许我向WORKERS添加数据。 在下面的示例中,我知道USERZ表中存在“ XXXXXXX1”,因此我想能够在WORKERS表中添加此用户。
例如:
"INSERT INTO WORKERS (ID) VALUES ('XXXXXXX1') "
谢谢 !
您也不应将主键ID设置为外键。 重构成这样
CREATE TABLE IF NOT EXISTS WORKERS (
ID CHAR(8) NOT NULL PRIMARY KEY,
USER_ID CHAR(8) NOT NULL,
DATE_START TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
DATE_END TIMESTAMP NULL,
FOREIGN KEY (USER_ID) REFERENCES USERZ (ID)
) ENGINE=INNODB DEFAULT CHARACTER SET = utf8 COLLATE = utf8_general_ci;)
然后您的插入内容应该是
INSERT INTO WORKERS (USER_ID) VALUES ('XXXXXXX1')
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