day02-数据库操作

一、数据库操作

1.1、创建数据库(增)

CREATE DATABASE 也可以使用小写,(注意不要漏掉分号 ;)

mysql> create database test;
或
mysql> create database test charset utf8;

1.2、删除数据库(删)

mysql> drop database test;

1.3、修改数据库(改)

mysql> alter database test charset gbk;

1.4、查看数据库(查)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
| test               |
+--------------------+
5 rows in set (0.00 sec)

查看mysql模式(一定要是严格模式)

mysql> select @@sql_mode;
+--------------------------------------------+
| @@sql_mode                                 |
+--------------------------------------------+
| STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION |
+--------------------------------------------+
1 row in set (0.00 sec)

二、数据库表操作

2.1、指定数据库,或者称为切换数据库,后面的操作都会针对这个数据库进行

mysql> use test;
Database changed

查看当前所在文件夹

mysql> select database();

2.2、创建表user实例(增)

mysql> create table employee (id int(10),name char(20),phone int(12));

mysql> create table user 
-> (
-> id int(10),
-> name varchar(20),
-> type varchar(20)
-> );

2.3、删除数据库表(删)

mysql> drop table user;

2.4、修改数据库表(改)

# modify修改的意思
mysql> alter table user modify name char(6);
# 改变name为大写的NAME
mysql> alter table user change name NAMA char(7);

2.5、查看数据库表(查)

#查看当前的这张user表
mysql> show create table user;

# 查看所有的表
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| user           |
+----------------+

# 查看表结构的详细信息
mysql> desc user;
或
mysql> describe user;
+----------+-------------+------+-----+---------+----------------+
| Field    | Type        | Null | Key | Default | Extra          |
+----------+-------------+------+-----+---------+----------------+
| id       | int(11)     | NO   | PRI | NULL    | auto_increment |
| username | varchar(20) | NO   |     | NULL    |                |
| password | varchar(20) | NO   |     | NULL    |                |
| type     | varchar(20) | NO   |     | NULL    |                |
+----------+-------------+------+-----+---------+----------------+

2.6、复制表

复制表结构+记录 (key不会复制: 主键、外键和索引)

mysql> create table new_user select * from user;

只复制表结构,不拷贝记录

mysql> create table new_user select * from user where 1=2;  
或
mysql> create table new_employee like employee;  

三、数据库表内容操作

3.1、增
# 插入一条数据,规定id,name数据类型

mysql> insert user(id, username, password, type) value(1, 'super', 'super123', 'super), (2, 'admin', 'admin123', 'admin');
或
mysql> insert into user value (1, 'super', 'super123', 'super');
mysql> insert into user value (2, 'admin', 'admin123', 'admin');

3.2、删

mysql> delete from user;
mysql> delete from user where id=2;

3.3、改

mysql> update db1.user set name='Tom';
mysql> update db1.user set name='Mike' where id=2;

3.4、查

mysql> select id from db1.user;
mysql> select id,name from db1.user;
mysql> select * from db1.user; 
或
mysql> select * from user;
+----+----------+----------+-------+
| id | username | password | type  |
+----+----------+----------+-------+
|  1 | super    | super    | super |
|  2 | admin    | admin    | admin |
+----+----------+----------+-------+

四、退出

使用命令 quit 或者 exit 退出 MySQL。

猜你喜欢

转载自www.cnblogs.com/dxnui119/p/10165313.html