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  • MYSQL入门操作和常规DML、DDL、DQL使用

    刷新权限,将某些权限从硬盘刷新到内存中(修改root密码自带隐式刷新权限操作)

    mysql> flush privileges;
    Query OK, 0 rows affected (0.00 sec)
    
    mysql> 
    

    查看服务端口

    mysql> show variables like 'port';
    +---------------+-------+
    | Variable_name | Value |
    +---------------+-------+
    | port          | 3306  |
    +---------------+-------+
    1 row in set (0.00 sec)
    
    mysql> 
    

    查看数据库字符集

    mysql> show variables like '%char%';
    +--------------------------+----------------------------------+
    | Variable_name            | Value                            |
    +--------------------------+----------------------------------+
    | character_set_client     | utf8                             |
    | character_set_connection | utf8                             |
    | character_set_database   | latin1                           |
    | character_set_filesystem | binary                           |
    | character_set_results    | utf8                             |
    | character_set_server     | latin1                           |
    | character_set_system     | utf8                             |
    | character_sets_dir       | /usr/local/mysql/share/charsets/ |
    +--------------------------+----------------------------------+
    8 rows in set (0.01 sec)
    

    切数据库

    mysql> select database();
    +------------+
    | database() |
    +------------+
    | test       |
    +------------+
    1 row in set (0.01 sec)
    
    mysql> show databases;
    +--------------------+
    | Database           |
    +--------------------+
    | information_schema |
    | mysql              |
    | performance_schema |
    | sys                |
    +--------------------+
    4 rows in set (0.00 sec)
    
    mysql> use mysql
    Reading table information for completion of table and column names
    You can turn off this feature to get a quicker startup with -A
    
    Database changed  
    mysql> select database();
    +------------+
    | database() |
    +------------+
    | mysql      |
    +------------+
    1 row in set (0.00 sec)
    mysql> status
    --------------
    mysql  Ver 14.14 Distrib 5.7.25, for linux-glibc2.12 (x86_64) using  EditLine wrapper
    
    Connection id:          6
    Current database:       mysql
    Current user:           root@localhost
    SSL:                    Not in use
    Current pager:          stdout
    Using outfile:          ''
    Using delimiter:        ;
    Server version:         5.7.25 MySQL Community Server (GPL)
    Protocol version:       10
    Connection:             Localhost via UNIX socket
    Server characterset:    latin1
    Db     characterset:    latin1
    Client characterset:    utf8
    Conn.  characterset:    utf8
    UNIX socket:            /tmp/mysql.sock
    Uptime:                 2 days 16 hours 47 min 41 sec
    
    Threads: 1  Questions: 58  Slow queries: 0  Opens: 138  Flush tables: 1  Open tables: 131  Queries per second avg: 0.000
    --------------
    
    
    mysql> show tables;
    +---------------------------+
    | Tables_in_mysql           |
    +---------------------------+
    | columns_priv              |
    | db                        |
    | engine_cost               |
    | event                     |
    | func                      |
    | general_log               |
    | gtid_executed             |
    | help_category             |
    | help_keyword              |
    | help_relation             |
    | help_topic                |
    | innodb_index_stats        |
    | innodb_table_stats        |
    | ndb_binlog_index          |
    | plugin                    |
    | proc                      |
    | procs_priv                |
    | proxies_priv              |
    | server_cost               |
    | servers                   |
    | slave_master_info         |
    | slave_relay_log_info      |
    | slave_worker_info         |
    | slow_log                  |
    | tables_priv               |
    | time_zone                 |
    | time_zone_leap_second     |
    | time_zone_name            |
    | time_zone_transition      |
    | time_zone_transition_type |
    | user                      |
    +---------------------------+
    31 rows in set (0.00 sec)
    
    mysql> 
    

    创建允许远程登陆的用户

    mysql> select host,user from mysql.user;
    +-----------+---------------+
    | host      | user          |
    +-----------+---------------+
    | localhost | mysql.session |
    | localhost | mysql.sys     |
    | localhost | root          |
    +-----------+---------------+
    3 rows in set (0.00 sec)
    
    mysql> grant all privileges on *.* to scott@'%' identified by 'tiger';
    Query OK, 0 rows affected, 1 warning (0.00 sec)
    
    mysql> 
    

    data目录中每个数据库都创建了一个文件夹,lbdata1、ib_logfile0、ib_logfile1三个是专门为innodb存放数据和日志的共享文件

    mysql> create database test;
    Query OK, 1 row affected (0.01 sec)
    
    mysql> use test;
    Database changed
    mysql> create table tmp(id int);
    Query OK, 0 rows affected (0.03 sec)
    
    mysql> desc tmp;
    +-------+---------+------+-----+---------+-------+
    | Field | Type    | Null | Key | Default | Extra |
    +-------+---------+------+-----+---------+-------+
    | id    | int(11) | YES  |     | NULL    |       |
    +-------+---------+------+-----+---------+-------+
    1 row in set (0.02 sec)
    
    mysql> insert into tmp value ('2')
        -> ;
    Query OK, 1 row affected (0.01 sec)
    
    mysql> commit;
    Query OK, 0 rows affected (0.00 sec)
    
    mysql> select * from tmp;
    +------+
    | id   |
    +------+
    |    2 |
    +------+
    1 row in set (0.00 sec)
    
    mysql> q
    Bye
    [root@localhost /usr/local/mysql/data]$ ls
    auto.cnf  ib_buffer_pool  ibdata1  ib_logfile0  ib_logfile1  ibtmp1  localhost.localdomain.err  localhost.localdomain.pid  mysql  performance_schema  sys  test
    [root@localhost /usr/local/mysql/data]$ cd test
    [root@localhost /usr/local/mysql/data/test]$ ls
    db.opt  tmp.frm  tmp.ibd
    

    每个数据库目录中的db.opt是数据库的信息,表名.frm是表的元信息,表名.ibd是数据信息,其中innodb_file_per_table参数来控制是否单独存储,5.7默认on,之前版本默认off

    mysql> show variables like '%per_table%';
    +-----------------------+-------+
    | Variable_name         | Value |
    +-----------------------+-------+
    | innodb_file_per_table | ON    |
    +-----------------------+-------+
    1 row in set (0.01 sec)
    
    mysql> 
    

    .myd .myi是老的MyISAM存储引擎,myi是索引信息

    mysql> create table tmp2(id int);
    Query OK, 0 rows affected (0.02 sec)
    
    mysql>  show create table tmp;
    +-------+-----------------------------------------------------------------------------------------+
    | Table | Create Table                                                                            |
    +-------+-----------------------------------------------------------------------------------------+
    | tmp   | CREATE TABLE `tmp` (
      `id` int(11) DEFAULT NULL
    ) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
    +-------+-----------------------------------------------------------------------------------------+
    1 row in set (0.00 sec)
    
    mysql> 
    
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  • 原文地址:https://www.cnblogs.com/yongestcat/p/11371604.html
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