Mysql-数据库、表建立和删除以及增删改查

一、数据库创建和删除

1.1、创建数据库

mysql> create database if not exists test;

1.2修改数据库默认编码

mysql> alter database test default character set utf8 collate utf8_bin;

1.3、删除数据库

mysql> drop database if exists test;

二、创建表、删除表、修改表字段和表编码方式

2.1 创建表

create table if not exists stu(id int(11) not null auto_increment,name varchar(20),primary key(id))engine=Innodb default charset=utf8;

mysql> desc stu;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| id    | int(11)     | NO   |     | NULL    |       |
| name  | varchar(20) | YES  |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+

2.2 修改表字段属性和字段名

mysql> alter table stu modify name varchar(50);//修改表
mysql> desc stu;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| id    | int(11)     | NO   |     | NULL    |       |
| name  | varchar(50) | YES  |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+

mysql> alter table stu change name gender varchar(20);//修改字段名
mysql> desc stu;
+--------+-------------+------+-----+---------+----------------+
| Field  | Type        | Null | Key | Default | Extra          |
+--------+-------------+------+-----+---------+----------------+
| id     | int(11)     | NO   | PRI | NULL    | auto_increment |
| gender | varchar(20) | YES  |     | NULL    |                |
+--------+-------------+------+-----+---------+----------------+

2.3 在表中添加一行

mysql> alter table stu add column gender varchar(20);
mysql> desc stu;
+--------+-------------+------+-----+---------+-------+
| Field  | Type        | Null | Key | Default | Extra |
+--------+-------------+------+-----+---------+-------+
| id     | int(11)     | NO   |     | NULL    |       |
| name   | varchar(50) | YES  |     | NULL    |       |
| gender | varchar(20) | YES  |     | NULL    |       |
+--------+-------------+------+-----+---------+-------+

2.4 删除表中某一行

mysql> alter table stu drop column gender;
mysql> desc stu;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| id    | int(11)     | NO   |     | NULL    |       |
| name  | varchar(50) | YES  |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+

2.5 修改表名

 mysql> alter table stu rename student;
 mysql> desc student;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| id    | int(11)     | NO   |     | NULL    |       |
| name  | varchar(50) | YES  |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+

2.6查看表的存储引擎、编码方式

mysql> show create table stu;
+-------+-------------------------------------------------+
| Table | Create Table                                                                                                                                             |
+-------+-------------------------------------------------+
| stu   | CREATE TABLE `stu` (
  `id` int(11) NOT NULL,
  `name` varchar(20) CHARACTER SET utf8 DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin |
+-------+-------------------------------------------------+

2.7 修改表的编码方式

mysql> alter table stu default character set utf8 collate utf8_bin; 

2.6 删除表

mysql> drop table if exists student;
mysql> show tables;
Empty set (0.00 sec)

三、增删改查

3.1 向数据库中插入一条数据（insert into…）

insert into stu(name) values('Zou Baitao');

3.2 查询数据库信息（select… from..）

mysql> select name from stu;
+------------+
| name       |
+------------+
| Zou Baitao |
+------------+

3.3修改数据库信息（update …set..）

mysql> update stu set name='Li Gang' where id = 1;
mysql> select *from stu where id = 1;
+----+---------+
| id | name    |
+----+---------+
|  1 | Li Gang |
+----+---------+

3.4删除数据库某一行（delete from ….）

mysql> delete from stu where id = 1;
mysql> select *from stu;
Empty set (0.00 sec)