mysql --- 创建数据库

Posted 2021-03-22 从前慢

1、每创建一个数据库，在mysql的data文件夹里会创建一个目录，数据库名就是目录名

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

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| phone_num          |
| sys                |
+--------------------+
5 rows in set (0.00 sec)

　　查看data文件，有phone_num这个文件夹

 cd /usr/local/mysql/data
[root@iz2zedr8770rctry7tq8t7z data]# ls
auto.cnf  ib_buffer_pool  ibdata1  ib_logfile0  ib_logfile1  ibtmp1  iz2zedr8770rctry7tq8t7z.pid  mysql  performance_schema  phone_num  sys

 

2、创建表

mysql> use phone_num
Database changed
mysql> create table phone_num_data
    -> (case_id INT(4) PRIMARY KEY,
    -> phone_num INT(11) );
Query OK, 0 rows affected (0.01 sec)

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

 

3、查看表结构

mysql> desc phone_num_data ;
+-----------+---------+------+-----+---------+-------+
| Field     | Type    | Null | Key | Default | Extra |
+-----------+---------+------+-----+---------+-------+
| case_id   | int(4)  | NO   | PRI | NULL    |       |
| phone_num | int(11) | YES  |     | NULL    |       |
+-----------+---------+------+-----+---------+-------+
2 rows in set (0.00 sec)

 

4、想更改数据库名，从1中可以知道，直接改文件名就可以啦

[root@iz2zedr8770rctry7tq8t7z data]# ls
auto.cnf  ib_buffer_pool  ibdata1  ib_logfile0  ib_logfile1  ibtmp1  iz2zedr8770rctry7tq8t7z.pid  mysql  performance_schema  phone_num  sys
[root@iz2zedr8770rctry7tq8t7z data]# mv phone_num test_cases
[root@iz2zedr8770rctry7tq8t7z data]# ls
auto.cnf  ib_buffer_pool  ibdata1  ib_logfile0  ib_logfile1  ibtmp1  iz2zedr8770rctry7tq8t7z.pid  mysql  performance_schema  sys  test_cases

　　改完啦，查询看看吧

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
| test_cases         |
+--------------------+
5 rows in set (0.00 sec)

　　不要改了，改完就报错

mysql> desc phone_num_data;
ERROR 1146 (42S02): Table ‘test_cases.phone_num_data‘ doesn‘t exist

 

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