mysql 外键的记载

mysql> show create table tb_dept1;
+----------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table    | Create Table                                                                                                                                                                                                                 |
+----------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tb_dept1 | CREATE TABLE `tb_dept1` (
`id` int(11) NOT NULL,
`name` varchar(22) CHARACTER SET latin1 NOT NULL,
`location` varchar(50) CHARACTER SET latin1 DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+----------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> create table tb_emp5
->     (
->      id int(11) primary key,
->      name varchar(25),
->      deptId int(11),
->      salary float,
->      constraint fk_emp_dept1 foreign key (deptId) references tb_dept1(id)
->      ) ENGINE=InnoDB Default charset=utf8;
Query OK, 0 rows affected (0.03 sec)

mysql> desc tb_dept1;
+----------+-------------+------+-----+---------+-------+
| Field    | Type        | Null | Key | Default | Extra |
+----------+-------------+------+-----+---------+-------+
| id       | int(11)     | NO   | PRI | NULL    |       |
| name     | varchar(22) | NO   |     | NULL    |       |
| location | varchar(50) | YES  |     | NULL    |       |
+----------+-------------+------+-----+---------+-------+
3 rows in set (0.00 sec)

mysql> insert into tb_dept1 values('1','技术部','xxxxxxxx');
Query OK, 1 row affected (0.01 sec)

mysql> insert into tb_emp5 values('1','xx','2','3300');
ERROR 1452 (23000): Cannot add or update a child row: a foreign key constraint fails (`lisheng`.`tb_emp5`, CONSTRAINT `fk_emp_dept1` FOREIGN KEY (`deptId`) REFERENCES `tb_dept1` (`id`))
mysql> insert into tb_emp5 values('1','xx','1','3300');
Query OK, 1 row affected (0.02 sec)

mysql> select * from tb_emp5;
+----+--------+--------+--------+
| id | name   | deptId | salary |
+----+--------+--------+--------+
|  1 | xx |      1 |   3300 |
+----+--------+--------+--------+
1 row in set (0.00 sec)

mysql> select * from tb_dept1;
+----+-----------+--------------------+
| id | name      | location           |
+----+-----------+--------------------+
|  1 | 技术部     |   xxxxxxxxxx |
+----+-----------+--------------------+
1 row in set (0.00 sec)