MySQL 创建数据库 创建表

时间：2022-09-12 21:26:05

最近几天开始研究MySQL。那么先来看看最基本的MySQL操作。


1、使用SHOW语句找出在服务器上当前存在什么数据库： 

mysql> SHOW DATABASES; 
+----------+ 
| Database | 
+----------+ 
| mysql | 
| test | 
+----------+ 
3 rows in set (0.00 sec)



2、创建一个数据库starive 
 

mysql> CREATE DATABASE starive;


注意不同操作系统对大小写的敏感。 
3、选择你所创建的数据库 
 

mysql> USE starive
Database changed



此时你已经进入你刚才所建立的数据库starive. 
4、 创建一个数据库表 
首先看现在你的数据库中存在什么表： 
 
mysql> SHOW TABLES; Empty set (0.00 sec)


说明刚才建立的数据库中还没有数据库表。下面来创建一个数据库表Student, Course, SC :

CREATE TABLE Student
       (Sno  CHAR(9)  PRIMARY KEY,
        Sname  CHAR(20) NOT NULL,    
        Ssex  CHAR(4),
        Sage  SMALLINT,
        Sdept  CHAR(20)) engine= innodb;

    create table course(
      cno CHAR(6),
      cname varchar(20),
      credit int,
      primary key(cno)
      ) engine= innodb;

  CREATE TABLE SC
         (Sno    CHAR(9)  NOT NULL,
          Cno    CHAR(6)  NOT NULL, 
          Grade    SMALLINT,
          PRIMARY KEY (Sno,Cno),
          constraint f1 FOREIGN KEY (Sno) REFERENCES Student(Sno),
          FOREIGN KEY (Cno) REFERENCES Course(Cno)
      ) engine= innodb;
创建了表后，我们可以看看刚才做的结果，用SHOW TABLES显示数据库中有哪些表： 


 
mysql> show tables;+-------------------+
| Tables_in_starive |
+-------------------+
| course            |
| sc                |
| student           |
+-------------------+
3 rows in set (0.00 sec)



5、显示表的结构：  

mysql> describe student;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| Sno   | char(9)     | NO   | PRI | NULL    |       |
| Sname | char(20)    | NO   |     | NULL    |       |
| Ssex  | char(4)     | YES  |     | NULL    |       |
| Sage  | smallint(6) | YES  |     | NULL    |       |
| Sdept | char(20)    | YES  |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
5 rows in set (0.22 sec)


6、 往表中加入记录 
我们先用SELECT命令来查看表中的数据： 
 

mysql> select * from student; 
Empty set (0.00 sec)

这说明刚才创建的表还没有记录。 加入新记录： 

INSERT INTO Student VALUES('0201','赵伟','男',18,'cs');
INSERT INTO Student VALUES('0202','张力虹','男',19,'is');
INSERT INTO Student VALUES('0203','徐秀美','女',21,'is');
INSERT INTO Student VALUES('0204','刘平','男',20,'cs');
INSERT INTO Student VALUES('0205','姚家全','男',19,'cs');
INSERT INTO Student VALUES('0206','上关美云','女',23,'ma');

报错：

mysql> INSERT INTO Student VALUES('0201','赵伟','男',18,'cs');
ERROR 1366 (HY000): Incorrect string value: '\xD5\xD4\xCE\xB0' for column 'Snam
' at row 1
mysql> INSERT INTO Student VALUES('0202','张力虹','男',19,'is');
ERROR 1366 (HY000): Incorrect string value: '\xD5\xC5\xC1\xA6\xBA\xE7' for colu
n 'Sname' at row 1
mysql> INSERT INTO Student VALUES('0203','徐秀美','女',21,'is');
ERROR 1366 (HY000): Incorrect string value: '\xD0\xEC\xD0\xE3\xC3\xC0' for colu
n 'Sname' at row 1
mysql> INSERT INTO Student VALUES('0204','刘平','男',20,'cs');
ERROR 1366 (HY000): Incorrect string value: '\xC1\xF5\xC6\xBD' for column 'Snam
' at row 1
mysql> INSERT INTO Student VALUES('0205','姚家全','男',19,'cs');
ERROR 1366 (HY000): Incorrect string value: '\xBC\xD2\xC8\xAB' for column 'Snam
' at row 1
mysql> INSERT INTO Student VALUES('0206','上关美云','女',23,'ma');
ERROR 1366 (HY000): Incorrect string value: '\xC9\xCF\xB9\xD8\xC3\xC0...' for c
lumn 'Sname' at row 1
mysql> select * from student;
Empty set (0.02 sec)

解决方案是：

在装MYSQL的时候选择的是utf8，所以在插入数据的时候出现编码的错误，解决方法是找到Mysql的安装目录下的my.ini文件，把里面的default-character-set=gbk。 重新启动MySQL.


再次插入数据：

INSERT INTO Student VALUES('0201','赵伟','男',18,'cs');
INSERT INTO Student VALUES('0202','张力虹','男',19,'is');
INSERT INTO Student VALUES('0203','徐秀美','女',21,'is');
INSERT INTO Student VALUES('0204','刘平','男',20,'cs');
INSERT INTO Student VALUES('0205','姚家全','男',19,'cs');
INSERT INTO Student VALUES('0206','上关美云','女',23,'ma');

再用上面的SELECT命令看：

mysql> select * from student;
+------+----------+------+------+-------+
| Sno  | sname    | Ssex | Sage | Sdept |
+------+----------+------+------+-------+
| 0201 | 赵伟     | 男   |   18 | cs    |
| 0202 | 张力虹   | 男   |   19 | is    |
| 0203 | 徐秀美   | 女   |   21 | is    |
| 0204 | 刘平     | 男   |   20 | cs    |
| 0205 | 姚家全   | 男   |   19 | cs    |
| 0206 | 上关美云 | 女   |   23 | ma    |
+------+----------+------+------+-------+
6 rows in set (0.00 sec)

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