MySQL之终端Terminal（dos界面）管理数据库、数据表、数据的基本

我们再次使用desc查看PEOPLE表结构：

mysqlgt; 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)

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2.4.3 delete 删除表（列）字段

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

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删除后，再次查看PEOPLE表结构：

mysqlgt; 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。

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2.4.4 rename 重命名表名

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

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2.5 create 利用已有数据创建新表

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

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我们查看一下目前数据库存在的表：

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

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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。

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以下命令均在PEOPLE表上操作。

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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：

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

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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：

mysqlgt; 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。

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我们多添加几条数据，如：

mysqlgt; 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)

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3.2 删除数据（删）

mysqlgt; delete from PEOPLE where name = ‘Lisa‘;
Query OK, 1 row affected (0.01 sec)

mysqlgt; 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)

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

mysqlgt; 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)