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2015
03-03

MySQL终端管理数据库操作指南

MySQL有很多的可视化管理工具,比如“mysql-workbench”和“sequel-pro-”。 现在我写MySQL的终端命令操作的文章,是想强化一下自己对于MySQL的理解,总会比使用图形化的理解透彻,因为我本来就比较喜欢写代码。同时写出来这些文章,是想要给大家当个参考,希望也能对大家有所帮助,有所提升,这就是我为什么要写终端操作MySQL的文章了。

注意:MySQL数据库命令不区分大小写。但在MAC的终端,如果你想使用tab自动补全命令,那么你就必须使用大写,这样MAC的终端才会帮你补全命令,否则你按N遍tab都不会有响应。

1、数据库(database)管理

1.1 create 创建数据库

create database firstDB;

1.2 show 查看所有数据库

mysql> show databases;

+--------------------+
| Database           |
+--------------------+
| information_schema |
| firstDB            |
| mysql              |
| performance_schema |
+--------------------+
4 rows in set (0.00 sec)

1.3 alter 修改数据库

alter 命令修改数据库编码:

默认创建的数据库默认不支持中文字符,如果我们需要它支持中文字符,则将它的编码设置为utf8格式:

mysql> ALTER DATABASE testDB CHARACTER SET UTF8;
Query OK, 1 row affected (0.00 sec)

1.4 use 使用数据库

mysql> use firstDB;
Database changed

1.5 查看当前使用的数据库

mysql> select database();
+------------+
| database() |
+------------+
| firstdb    |
+------------+
1 row in set (0.00 sec)

1.6 drop 删除数据库

mysql> drop database firstDB;
Query OK, 0 rows affected (0.00 sec)

2、数据表(table)管理

我们首先创建一个数据库,提供我们往后的使用:

mysql> create database testDB;
Query OK, 1 row affected (0.00 sec)

创建后记得用use命令进入(使用)数据库,不然后面的操作都会不成功的。

2.1 create 创建表

mysql> create table PEOPLE (
    -> ID int AUTO_INCREMENT PRIMARY KEY,
    -> NAME varchar(20) not null,
    -> AGE int not null,
    -> BIRTHDAY datetime);                                                     
Query OK, 0 rows affected (0.01 sec)

2.2 show 显示表

显示当前数据库所有的数据表

mysql> show tables;
+------------------+
| Tables_in_testdb |
+------------------+
| PEOPLE           |
+------------------+
1 row in set (0.00 sec)

2.3 desc 查看表结构

mysql> desc PEOPLE
    -> ;
+----------+-------------+------+-----+---------+----------------+
| Field    | Type        | Null | Key | Default | Extra          |
+----------+-------------+------+-----+---------+----------------+
| ID       | int(11)     | NO   | PRI | NULL    | auto_increment |
| NAME     | varchar(20) | NO   |     | NULL    |                |
| AGE      | int(11)     | NO   |     | NULL    |                |
| BIRTHDAY | datetime    | YES  |     | NULL    |                |
+----------+-------------+------+-----+---------+----------------+
4 rows in set (0.01 sec)

2.4 alter 修改表结构(增、删、改)

默认创建的表不支持中文字符,所以需将表编码设置为utf8:

mysql> ALTER TABLE KEYCHAIN CONVERT TO CHARACTER SET UTF8;
Query OK, 1 row affected (0.02 sec)
Records: 1  Duplicates: 0  Warnings: 0

2.4.1 insert 在表中添加列(字段)

mysql> alter table PEOPLE add star BOOL;
Query OK, 0 rows affected (0.02 sec)
Records: 0  Duplicates: 0  Warnings: 0

提示:在MySQL里,布尔类型会自动转换为tinyint(1)类型。

我们不妨使用desc去查看一下PEOPLE表结构:

mysql> desc PEOPLE;
+----------+-------------+------+-----+---------+----------------+
| Field    | Type        | Null | Key | Default | Extra          |
+----------+-------------+------+-----+---------+----------------+
| ID       | int(11)     | NO   | PRI | NULL    | auto_increment |
| NAME     | varchar(20) | NO   |     | NULL    |                |
| AGE      | int(11)     | NO   |     | NULL    |                |
| BIRTHDAY | datetime    | YES  |     | NULL    |                |
| star     | tinyint(1)  | YES  |     | NULL    |                |
+----------+-------------+------+-----+---------+----------------+
5 rows in set (0.00 sec)

现在,你该相信我了吧?

2.4.2 alter 修改表(列)字段

mysql> alter table PEOPLE MODIFY star int;
Query OK, 0 rows affected (0.01 sec)
Records: 0  Duplicates: 0  Warnings: 0

我们再次使用desc查看PEOPLE表结构:

mysql> desc PEOPLE;
+----------+-------------+------+-----+---------+----------------+
| Field    | Type        | Null | Key | Default | Extra          |
+----------+-------------+------+-----+---------+----------------+
| ID       | int(11)     | NO   | PRI | NULL    | auto_increment |
| NAME     | varchar(20) | NO   |     | NULL    |                |
| AGE      | int(11)     | NO   |     | NULL    |                |
| BIRTHDAY | datetime    | YES  |     | NULL    |                |
| star     | int(11)     | YES  |     | NULL    |                |
+----------+-------------+------+-----+---------+----------------+
5 rows in set (0.00 sec)

2.4.3 delete 删除表(列)字段

mysql> alter table PEOPLE DROP column star;
Query OK, 0 rows affected (0.02 sec)
Records: 0  Duplicates: 0  Warnings: 0

删除后,再次查看PEOPLE表结构:

mysql> desc PEOPLE;
+----------+-------------+------+-----+---------+----------------+
| Field    | Type        | Null | Key | Default | Extra          |
+----------+-------------+------+-----+---------+----------------+
| ID       | int(11)     | NO   | PRI | NULL    | auto_increment |
| NAME     | varchar(20) | NO   |     | NULL    |                |
| AGE      | int(11)     | NO   |     | NULL    |                |
| BIRTHDAY | datetime    | YES  |     | NULL    |                |
+----------+-------------+------+-----+---------+----------------+
4 rows in set (0.00 sec)

删除字段成功,现在我们已经不能看到star的字段了。

2.4.4 rename 重命名表名

mysql> RENAME TABLE PEOPLE TO NEW_PEOPLE;
Query OK, 0 rows affected (0.00 sec)

2.5 create 利用已有数据创建新表

mysql> create table newTable select * from PEOPLE;
Query OK, 0 rows affected (0.01 sec)
Records: 0  Duplicates: 0  Warnings: 0

我们查看一下目前数据库存在的表:

mysql> show tables;
+------------------+
| Tables_in_testdb |
+------------------+
| PEOPLE           |
| newTable         |
+------------------+
2 rows in set (0.00 sec)

3、数据的操作及管理

数据表的基本操作,包含增、删、改、查数据。

以下命令均在PEOPLE表上操作。

3.1 增加数据(增)

PEOPLE表目前是没有数据的,它是空的数据表,我们现在先添加一些数据。

insert into 命令添加数据:

mysql> insert into PEOPLE VALUES (null, 'Anny', 22, '1992-05-22');
Query OK, 1 row affected (0.00 sec)

使用select命令查看表(会在后面介绍),现在我们查看PEOPLE数据表的数据:

mysql> select * from PEOPLE;
+----+------+-----+---------------------+
| ID | NAME | AGE | BIRTHDAY            |
+----+------+-----+---------------------+
|  1 | Anny |  22 | 1992-05-22 00:00:00 |
+----+------+-----+---------------------+
1 row in set (0.00 sec)

数据表现在有一条数据。

我们多添加几条数据,如:

mysql> select * from PEOPLE;
+----+--------+-----+---------------------+
| ID | NAME   | AGE | BIRTHDAY            |
+----+--------+-----+---------------------+
|  1 | Anny   |  22 | 1992-05-22 00:00:00 |
|  2 | Garvey |  23 | 1991-05-22 00:00:00 |
|  3 | Lisa   |  25 | 1989-05-22 00:00:00 |
|  4 | Nick   |  24 | 1990-05-22 00:00:00 |
|  5 | Rick   |  24 | 1991-05-22 00:00:00 |
+----+--------+-----+---------------------+
5 rows in set (0.00 sec)

3.2 删除数据(删)

delete 命令删除数据:

mysql> delete from PEOPLE where name = 'Lisa';
Query OK, 1 row affected (0.01 sec)

再次查询PEOPLE表:

mysql> select * from PEOPLE;
+----+--------+-----+---------------------+
| ID | NAME   | AGE | BIRTHDAY            |
+----+--------+-----+---------------------+
|  1 | Anny   |  22 | 1992-05-22 00:00:00 |
|  2 | Garvey |  23 | 1991-05-22 00:00:00 |
|  4 | Nick   |  24 | 1990-05-22 00:00:00 |
|  5 | Rick   |  24 | 1991-05-22 00:00:00 |
+----+--------+-----+---------------------+
4 rows in set (0.00 sec)

已经看不到名为“Lisa”的数据了。

3.3 修改数据(改)

update 命令修改数据:

mysql> update PEOPLE set name='Calvin' where name = 'Garvey';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

查询PEOPLE表内容:

mysql> select * from PEOPLE;
+----+--------+-----+---------------------+
| ID | NAME   | AGE | BIRTHDAY            |
+----+--------+-----+---------------------+
|  1 | Anny   |  22 | 1992-05-22 00:00:00 |
|  2 | Calvin |  23 | 1991-05-22 00:00:00 |
|  4 | Nick   |  24 | 1990-05-22 00:00:00 |
|  5 | Rick   |  24 | 1991-05-22 00:00:00 |
+----+--------+-----+---------------------+
4 rows in set (0.00 sec)

名为“Garvey”的记录已经修改为“Calvin”。

3.4 查询数据(查)

select 命令查询数据,最简单的就是查询表的所有数据,也就是我们最初使用到的那条命令:

mysql> select * from PEOPLE;
+----+--------+-----+---------------------+
| ID | NAME   | AGE | BIRTHDAY            |
+----+--------+-----+---------------------+
|  1 | Anny   |  22 | 1992-05-22 00:00:00 |
|  2 | Calvin |  23 | 1991-05-22 00:00:00 |
|  4 | Nick   |  24 | 1990-05-22 00:00:00 |
|  5 | Rick   |  24 | 1991-05-22 00:00:00 |
+----+--------+-----+---------------------+
4 rows in set (0.00 sec)

格式:select * from <表名>,*代表所有字段。

查询数据时也可指定显示的(列)字段:

mysql> select NAME, AGE, BIRTHDAY from PEOPLE;
+--------+-----+---------------------+
| NAME   | AGE | BIRTHDAY            |
+--------+-----+---------------------+
| Anny   |  22 | 1992-05-22 00:00:00 |
| Calvin |  23 | 1991-05-22 00:00:00 |
| Nick   |  24 | 1990-05-22 00:00:00 |
| Rick   |  24 | 1991-05-22 00:00:00 |
+--------+-----+---------------------+
4 rows in set (0.00 sec)

格式:select <字段名,字段名,…> from <表名>。

select查询命令还有很多的高级用法,比如用来查找不重复(distinct)的数据,使数据按条件排序(order by),按查询条件显示数据(where)等等。这些都会在下一篇文章作重点介绍,请大家继续留意我的博客,谢谢。

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