1. 简单mysql使用 建立数据库实例

1.启动数据库
ywx@ywx:/opt/mysql5151$ sudo ./bin/mysqld_safe --defaults-file=./my.cnf --user=ywx &

2.连接数据库
ywx@ywx:/opt/mysql5151$ sudo ./bin/mysql --defaults-file=./my.cnf


3.查看帮助

mysql> ?


讲述如何使用数据库。只有一张表，用于存储某公司员工的基本信息，为方便描述，这里是存储员工的部分信息，包括员工号、员工姓名、员工家庭住址、员工的收入、员工的级别
   

1.创建公司数据库
mysql> create database company;

2.创建员工信息表

mysql> use company;
Database changed
mysql> create table worker (nid int unique,name varchar(20),address varchar(200),salary float,level int);

3.插入数据

mysql> insert into workervalues(100,'tom','beijing',2000.0,0);
Query OK, 1 row affected (0.00 sec)

mysql> insert into worker values(101,'jim','shanghai',2000.
Query OK, 1 row affected (0.00 sec)

mysql> insert into worker values(102,'mail','shanghai',3000.
Query OK, 1 row affected (0.00 sec)

4.查询全部数据

mysql> select * from worker;
+------+------+----------+--------+-------+
| nid  | name | address  | salary | level |
+------+------+----------+--------+-------+
|  100 | tom  | beijing  |   2000 |     0 |
|  101 | jim  | shanghai |   2000 |     1 |
|  102 | mail | shanghai |   3000 |     2 |
+------+------+----------+--------+-------+
3 rows in set (0.00 sec)

5.删除其中一条记录

mysql> delete from worker where nid=100;
Query OK, 1 row affected (0.00 sec)

mysql> select * from worker; 这里已经少了 nid=100 的数据行了
+------+------+----------+--------+-------+
| nid  | name | address  | salary | level |
+------+------+----------+--------+-------+
|  101 | jim  | shanghai |   2000 |     1 |
|  102 | mail | shanghai |   3000 |     2 |
+------+------+----------+--------+-------+
2 rows in set (0.00 sec)

6.更新其中一条记录
将jim的level从1级到2级，slary从2000.0更新到3000.0

mysql> update worker set level=2,salary=3000.0 where nid =101;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select * from worker;                             +------+------+----------+--------+-------+
| nid  | name | address  | salary | level |
+------+------+----------+--------+-------+
|  101 | jim  | shanghai |   3000 |     2 |
|  102 | mail | shanghai |   3000 |     2 |
+------+------+----------+--------+-------+
2 rows in set (0.00 sec)

7.删除数据库
   1. 删除所有的数据表，
  

mysql> drop table worker;

   
   2. 删除数据库，

mysql> delete database company;