mysql實踐總結
阿新 • • 發佈:2017-09-14
read tails ted 增加 自動 err 搜索 where xxx
首先介紹mysql的安裝和基本使用、進階操作、講解mysql的導入導出和自動備份,然後介紹安全模式修改密碼和mysql的全文本搜索功能,最後記錄了個人使用mysql中遇到的問題集,閑暇時我也會多看幾次,鞏固下基礎吧。
基礎使用
sudo apt-get install mysql-common mysql-server
簡單使用:建庫
CREATE DATABASE IF NOT EXISTS yourdbname DEFAULT CHARSET utf8 COLLATE utf8_general_ci;
建表
create table MyClass(id int(4) not nullprimary key auto_increment,name char(20) not null,sex int(4) not null default ‘0‘,degree double(16,2));
增加
insert into MyClass values(1,‘Tom‘,96.45),(2,‘Joan‘,82.99), (2,‘Wang‘, 96.59);
刪除
delete from MyClass where id=1;
修改
update MyClass set name=‘Mary‘ where id=1;
查詢
select * from MyClass;
顯示所有視圖
select * from information_schema.TABLES where table_type=‘view‘ AND table_schema = ‘數據庫名‘;
創建用戶
create user xxx identified by ‘password‘;
重命名
rename user aaa to bbb;
刪除用戶
drop user aaa;
顯示權限
show grants for aaa(用戶);
授予權限
grant select on xxx(數據庫).* to aaa(用戶);
授予某個數據庫的全部權限
grant all on xxx(數據庫).* to aaa(用戶); grant all on xxx(數據庫).* to aaa(用戶)@localhost;
取消授權
revoke all on *.* from aaa(用戶)@localhost;
修改權限
GRANT ALL PRIVILEGES ON *.* TO ‘root‘@‘%’ WITH GRANT OPTION;
以上操作完成之後記得刷新權限:
flush privileges;
導入導出
導出數據和表結構:
mysqldump -uroot -p abc(數據庫名) > abc.sql
敲回車後輸入密碼
只導出表結構
mysqldump -uroot -p -d abc > abc.sql
導入數據庫
1、首先建空數據庫
mysql> create database abc;
2、導入數據庫
mysql -u root -p abc(數據庫名) < abc.sql
數據庫自動備份
新建備份腳本xxx.sh,輸入以下內容
#!/bin/bash # 要備份的數據庫名,多個數據庫用空格分開 databases=("db1", "db2") # 備份文件要保存的目錄,註意當前用戶必須用戶保存目錄的讀寫權限 basepath=‘/root/backup/mysql/‘ if [ ! -d "$basepath" ]; then mkdir -p "$basepath" fi # 循環databases數組 for db in ${databases[*]} do # 備份數據庫生成SQL文件 nice -n 19 /usr/bin/mysqldump -uroot -pcd32d5e86e --database $db > $basepath$db-$(date +%Y%m%d).sql # 將生成的SQL文件壓縮 nice -n 19 tar zPcf $basepath$db-$(date +%Y%m%d).sql.tar.gz -C $basepath $db-$(date +%Y%m%d).sql # 刪除7天之前的備份數據 find $basepath -mtime +7 -name "*.sql.tar.gz" -exec rm -rf {} \; done # 刪除生成的SQL文件 rm -rf $basepath/*.sql
使用crontab設置定時任務,在終端輸入crontab -e,加入以下內容,此任務為每天3點自動執行。
0 3 * * * bash xxx.sh(此處填寫腳本絕對地址)
開啟日誌記錄
[mysqld] server-id = 1 log_bin = /var/log/mysql/mysql-bin.log max_binlog_size = 1000M binlog-format = row
安全模式操作
進入安全模式修改密碼
mysqld_safe --skip-grant-tables & select user,host,password from user where user="root"
不同版本的mysql修改用戶密碼方式不一樣,需要查看mysql->user中的密碼字段,如果不是password的話就是authentication_string。
authentication_string的修改方式不太一樣:
use mysql; update user set authentication_string=PASSWORD("") where User=‘root‘; update user set plugin="mysql_native_password"; flush privileges; quit; sudo /etc/init.d/mysql stop sudo /etc/init.d/mysql start
如果不是authentication_string,則可用以下方法。
update user set password=PASSWORD("your_password") where user="root" and host=“localhost"
新操作
Mysql全文本搜索
Mysql5.6之後支持InnoDB,中文的全文本搜索,內置使用n-gram為分詞處理器,還支持中文~。
創建索引
create fulltext index ngram_idx on tag(Title) with parser ngram;
或
alter table tag add fulltext index ngram_idx(Title) with parser ngram;
獲取支持的最小分詞長度
SHOW VARIABLES LIKE ‘ft_min_word_len‘; //unix系統可在/etc/my.cnf中修改 [mysqld] ft_min_word_len = 1
開始使用
select Title,match(Title) against(‘清水‘) from tag ;
可能出現的問題集:
- 描述
2017-05-04T01:21:32.004560Z mysqld_safe Logging to ‘/var/log/mysql/error.log‘. 2017-05-04T01:21:32.023009Z mysqld_safe A mysqld process already exists
解決方法:
$ sudo killall mysqld
- 描述
2017-05-04T01:22:26.486677Z mysqld_safe Logging to ‘/var/log/mysql/error.log‘. 2017-05-04T01:22:26.488204Z mysqld_safe Directory ‘/var/run/mysqld‘ for UNIX socket file don‘t exists.
解決方法:
sudo mkdir -p /var/run/mysqld sudo chown -R mysql:mysql /var/run/mysqld
- 描述
$ sudo /etc/init.d/mysql start ies: No such file or directory job-working-directory: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory [....] Starting mysql (via systemctl): mysql.servicejob-working-directory: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory Job for mysql.service failed because the control process exited with error code. See "systemctl status mysql.service" and "journalctl -xe" for details.
解決方法:
當前文件夾不是實際目錄導致
cd到一個實際目錄位置即可
- 描述
sudo /etc/init.d/mysql start shell-init: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory job-working-directory: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory job-working-directory: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory job-working-directory: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory job-working-directory: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory job-working-directory: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory job-working-directory: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory job-working-directory: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory [....] Starting mysql (via systemctl): mysql.servicejob-working-directory: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory Job for mysql.service failed because the control process exited with error code. See "systemctl status mysql.service" and "journalctl -xe" for details.
按照提示:See "systemctl status mysql.service" and "journalctl -xe" for details. 但是並麽有什麽卵用,直接看mysql的log:/var/log/mysql/error.log 2017-05-04T01:37:56.583745Z 0 [Note] InnoDB: Check that you do not already have another mysqld process using the same InnoDB data or log files.
解決方法:
殺掉所有mysqld進程:killall mysqld
再次sudo /etc/init.d/mysql start 成功
- 描述
dpkg被鎖定
解決方法
sudo rm /var/cache/apt/archives/lock sudo rm /var/lib/dpkg/lock
mysql實踐總結