MySQL学习笔记5：修改表(alter table)

复制代码 代码如下:

mysql> alter table student rename person;
Query OK, 0 rows affected (0.03 sec)

复制代码 代码如下:

mysql> alter table person modify name varchar(20);
Query OK, 0 rows affected (0.18 sec)
Records: 0 Duplicates: 0 Warnings: 0

复制代码 代码如下:

mysql> alter table person change stu_name name varchar(25);
Query OK, 0 rows affected (0.20 sec)
Records: 0 Duplicates: 0 Warnings: 0

复制代码 代码如下:

mysql> alter table person add sex boolean;
Query OK, 0 rows affected (0.21 sec)
Records: 0 Duplicates: 0 Warnings: 0

复制代码 代码如下:

mysql> alter table person add age int not null;
Query OK, 0 rows affected (0.17 sec)
Records: 0 Duplicates: 0 Warnings: 0

复制代码 代码如下:

mysql> alter table person add num int primary key first;
Query OK, 0 rows affected (0.20 sec)
Records: 0 Duplicates: 0 Warnings: 0

复制代码 代码如下:

mysql> alter table person add birth date after name;
Query OK, 0 rows affected (0.20 sec)
Records: 0 Duplicates: 0 Warnings: 0

复制代码 代码如下:

mysql> alter table person drop sex;
Query OK, 0 rows affected (0.18 sec)
Records: 0 Duplicates: 0 Warnings: 0

复制代码 代码如下:

mysql> alter table person modify id int first;
Query OK, 0 rows affected (0.20 sec)
Records: 0 Duplicates: 0 Warnings: 0

复制代码 代码如下:

mysql> alter table person modify name varchar(25) after id;
Query OK, 0 rows affected (0.18 sec)
Records: 0 Duplicates: 0 Warnings: 0

复制代码 代码如下:

mysql> alter table user rename person;
Query OK, 0 rows affected (0.05 sec)

复制代码 代码如下:

mysql> alter table score add constraint fk foreign key(stu_id) references student(id);
Query OK, 10 rows affected (0.18 sec)
Records: 10 Duplicates: 0 Warnings: 0

复制代码 代码如下:

mysql> alter table student3 drop foreign key fk;
Query OK, 0 rows affected (0.18 sec)
Records: 0 Duplicates: 0 Warnings: 0