一、創建數據庫
mysql> create database company; mysql> use company;
二、創建表
1. 創建表offices
mysql> create table offices
-> (
-> officeCode int(10) NOT NULL UNIQUE,
-> city varchar(50) NOT NULL,
-> address varchar(50) NOT NULL,
-> country varchar(50) NOT NULL,
-> postalCode varchar(15) NOT NULL,
-> PRIMARY KEY (officeCode)
-> );
2. 創建表employees
mysql> create table employees
-> (
-> employeeNumber int(11) NOT NULL PRIMARY KEY AUTO_INCREMENT,
-> lastName VARCHAR(50) NOT NULL,
-> firstName VARCHAR(50) NOT NULL,
-> mobile VARCHAR(25) NOT NULL,
-> officeCode int(10) NOT NULL,
-> jobTitle VARCHAR(50) NOT NULL,
-> birth DATETIME,
-> note VARCHAR(255),
-> sex VARCHAR(5),
-> CONSTRAINT office_fk FOREIGN KEY (officeCode) REFERENCES offices(officeCode)
-> );
3. 查看數據庫已創建的表
mysql> show tables; +-------------------+ | Tables_in_company | +-------------------+ | employees | | offices | +-------------------+
mysql> desc offices; +------------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +------------+-------------+------+-----+---------+-------+ | officeCode | int(10) | NO | PRI | NULL | | | city | varchar(50) | NO | | NULL | | | address | varchar(50) | NO | | NULL | | | country | varchar(50) | NO | | NULL | | | postalCode | varchar(15) | NO | | NULL | | +------------+-------------+------+-----+---------+-------+
mysql> desc employees; +----------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------------+--------------+------+-----+---------+----------------+ | employeeNumber | int(11) | NO | PRI | NULL | auto_increment | | lastName | varchar(50) | NO | | NULL | | | firstName | varchar(50) | NO | | NULL | | | mobile | varchar(25) | NO | | NULL | | | officeCode | int(10) | NO | MUL | NULL | | | jobTitle | varchar(50) | NO | | NULL | | | birth | datetime | YES | | NULL | | | note | varchar(255) | YES | | NULL | | | sex | varchar(5) | YES | | NULL | | +----------------+--------------+------+-----+---------+----------------+
三、表的基本操作
1. 將表employees的mobile字段修改到officeCode字段後面
mysql> alter table employees MODIFY mobile varchar(25) after officeCode; mysql> desc employees; +----------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------------+--------------+------+-----+---------+----------------+ | employeeNumber | int(11) | NO | PRI | NULL | auto_increment | | lastName | varchar(50) | NO | | NULL | | | firstName | varchar(50) | NO | | NULL | | | officeCode | int(10) | NO | MUL | NULL | | | mobile | varchar(25) | YES | | NULL | | | jobTitle | varchar(50) | NO | | NULL | | | birth | datetime | YES | | NULL | | | note | varchar(255) | YES | | NULL | | | sex | varchar(5) | YES | | NULL | | +----------------+--------------+------+-----+---------+----------------+2. 將表employees的birth字段改名為employee_birth
mysql> alter table employees CHANGE birth employee_birth DATETIME; mysql> desc employees; +----------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------------+--------------+------+-----+---------+----------------+ | employeeNumber | int(11) | NO | PRI | NULL | auto_increment | | lastName | varchar(50) | NO | | NULL | | | firstName | varchar(50) | NO | | NULL | | | officeCode | int(10) | NO | MUL | NULL | | | mobile | varchar(25) | YES | | NULL | | | jobTitle | varchar(50) | NO | | NULL | | | employee_birth | datetime | YES | | NULL | | | note | varchar(255) | YES | | NULL | | | sex | varchar(5) | YES | | NULL | | +----------------+--------------+------+-----+---------+----------------+3. 修改sex字段，數據類型為CHAR(1),非空約束
mysql> alter table employees MODIFY sex CHAR(1) NOT NULL; mysql> desc employees; +----------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------------+--------------+------+-----+---------+----------------+ | employeeNumber | int(11) | NO | PRI | NULL | auto_increment | | lastName | varchar(50) | NO | | NULL | | | firstName | varchar(50) | NO | | NULL | | | officeCode | int(10) | NO | MUL | NULL | | | mobile | varchar(25) | YES | | NULL | | | jobTitle | varchar(50) | NO | | NULL | | | employee_birth | datetime | YES | | NULL | | | note | varchar(255) | YES | | NULL | | | sex | char(1) | NO | | NULL | | +----------------+--------------+------+-----+---------+----------------+4. 刪除字段note
mysql> alter table employees DROP note; mysql> desc employees; +----------------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------------+-------------+------+-----+---------+----------------+ | employeeNumber | int(11) | NO | PRI | NULL | auto_increment | | lastName | varchar(50) | NO | | NULL | | | firstName | varchar(50) | NO | | NULL | | | officeCode | int(10) | NO | MUL | NULL | | | mobile | varchar(25) | YES | | NULL | | | jobTitle | varchar(50) | NO | | NULL | | | employee_birth | datetime | YES | | NULL | | | sex | char(1) | NO | | NULL | | +----------------+-------------+------+-----+---------+----------------+5. 增加字段名favoriate_activity, 數據類型為VARCHAR(100)
mysql> alter table employees ADD favoriate_activity varchar(100); mysql> desc employees; +--------------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +--------------------+--------------+------+-----+---------+----------------+ | employeeNumber | int(11) | NO | PRI | NULL | auto_increment | | lastName | varchar(50) | NO | | NULL | | | firstName | varchar(50) | NO | | NULL | | | officeCode | int(10) | NO | MUL | NULL | | | mobile | varchar(25) | YES | | NULL | | | jobTitle | varchar(50) | NO | | NULL | | | employee_birth | datetime | YES | | NULL | | | sex | char(1) | NO | | NULL | | | favoriate_activity | varchar(100) | YES | | NULL | | +--------------------+--------------+------+-----+---------+----------------+6. 刪除表offices
1) 創建表時設置了表的外鍵，所以不能直接刪除
mysql> drop table offices; ERROR 1217 (23000): Cannot delete or update a parent row: a foreign key constraint fails2) 刪除employees表的外鍵約束
mysql> alter table employees drop foreign key office_fk;3) 刪除offices表
mysql> drop table offices; Query OK, 0 rows affected (0.03 sec)
mysql> show tables; +-------------------+ | Tables_in_company | +-------------------+ | employees | +-------------------+7. 修改employees表的存儲引擎為MyISAM
mysql> alter table employees ENGINE=MyISAM;
Query OK, 0 rows affected (0.12 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql> show create table employees\G;
*************************** 1. row ***************************
Table: employees
Create Table: CREATE TABLE `employees` (
`employeeNumber` int(11) NOT NULL AUTO_INCREMENT,
`lastName` varchar(50) NOT NULL,
`firstName` varchar(50) NOT NULL,
`officeCode` int(10) NOT NULL,
`mobile` varchar(25) DEFAULT NULL,
`jobTitle` varchar(50) NOT NULL,
`employee_birth` datetime DEFAULT NULL,
`sex` char(1) NOT NULL,
`favoriate_activity` varchar(100) DEFAULT NULL,
PRIMARY KEY (`employeeNumber`),
KEY `office_fk` (`officeCode`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
1 row in set (0.01 sec)
8. 將表employees表名改為employees_info
mysql> alter table employees rename employees_info; Query OK, 0 rows affected (0.00 sec) mysql> show tables; +-------------------+ | Tables_in_company | +-------------------+ | employees_info | +-------------------+ 1 row in set (0.00 sec)
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