数据库服务端可以服务多种类型的客户端
客户端可以是自己开发的,也可以是python代码编写的,也可以是其他编程语言编写的
须知:
1、SQL有时又也指代关系型数据库
2、NoSQL有时候也指代非关系型数据库
为了更方便的理解数据库的概念,将数据库分成了下列三种表述方式
用法:
create database 库名;
mysql> create database userinfor;
Query OK, 1 row affected (0.00 sec)
用法:
show databases;用法:
show create database 库名;mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| test |
| userinfor |
+--------------------+
5 rows in set (0.00 sec)
########################################################
show create database userinfor;
---------------------------------------
mysql> show create database userinfor;
+-----------+----------------------------------------------------------------------+
| Database | Create Database |
+-----------+----------------------------------------------------------------------+
| userinfor | CREATE DATABASE `userinfor` /*!40100 DEFAULT CHARACTER SET latin1 */ |
+-----------+----------------------------------------------------------------------+
1 row in set (0.00 sec)
用法:
mysql> alter database userinfor charset='utf8';
Query OK, 1 row affected (0.02 sec)
用法:
use 库名;
mysql> use userinfo;
Database changed
注意事项:
操作之前需要先确定库
用法:
create table 表名(字段名1 字段类型,字段名2 字段类型,..)
mysql> create table t1(name varchar(24),age int, gender varchar(23));
Query OK, 0 rows affected (0.01 sec)
用法:
mysql> show tables;
+--------------------+
| Tables_in_userinfo |
+--------------------+
| t1 |
| t2 |
| t3 |
| t4 |
| t6 |
+--------------------+
5 rows in set (0.00 sec)
mysql> show create table t1;
+-------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table
|
+-------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------+
| t1 | CREATE TABLE `t1` (
`name` varchar(24) DEFAULT NULL,
`age` int(11) DEFAULT NULL,
`gender` varchar(23) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
mysql> desc t1;
+--------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------+-------------+------+-----+---------+-------+
| name | varchar(24) | YES | | NULL | |
| age | int(11) | YES | | NULL | |
| gender | varchar(23) | YES | | NULL | |
+--------+-------------+------+-----+---------+-------+
3 rows in set (0.02 sec)
用法:
mysql> alter table t6 rename t5;
Query OK, 0 rows affected (0.00 sec)
mysql> drop table t5;
Query OK, 0 rows affected (0.00 sec)
用法:
insert into 表名 values(数据值1,数据值2, ...)
mysql> insert into t1 values('kangkang', 18 ,'male'),('lizhi', 18 ,'male');
Query OK, 1 row affected (0.01 sec)
用法:
mysql> select * from userinfo.t1;
+----------+------+--------+
| name | age | gender |
+----------+------+--------+
| kangkang | 18 | male |
| lizhi | 18 | male |
+----------+------+--------+
用法:
mysql> update t1 set name='kangk' where name='kangkang';
Query OK, 1 row affected (0.02 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> delete from t1;
Query OK, 2 rows affected (0.00 sec)
mysql> select * from userinfo.t1;
Empty set (0.00 sec)
mysql> delete from t1 where name='lizhi';
Query OK, 1 row affected (0.00 sec)
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