Ubuntumysql卸载
转自:http://blog.csdn.net/mzlqh/article/details/7621307
卸载mysql
第一步
1 |
sudo apt-get autoremove --purge mysql-server-5.0
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2 |
sudo apt-get remove mysql-server
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3 |
sudo apt-get autoremove mysql-server
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4 |
sudo apt-get remove mysql-common (非常重要)
|
1 |
dpkg -l | grep ^rc| awk '{print $2}' | sudo xargs dpkg -P
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第三步:安装 mysql
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sudo apt-get install mysql-server
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2 |
sudo apt-get install mysql-client
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3 |
sudo apt-get install php5-mysql(安装php5-mysql 是将php和mysql连接起来 )
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一旦安装完成,MySQL 服务器应该自动启动。您可以在终端提示符后运行以下命令来检查 MySQL 服务器是否正在运行:
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sudo netstat -tap | grep mysql
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当您运行该命令时,您可以看到类似下面的行:
tcp 0 0 localhost.localdomain:mysql *:* LISTEN -
如果服务器不能正常运行,您可以通过下列命令启动它:
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sudo /etc/init.d/mysql restart
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进入mysql
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$mysql -uroot -p 管理员密码 |
配置 MySQL 的管理员密码:
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sudo mysqladmin -u root password newpassword
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MySQLstringtypesincludeVARCHAR,TEXT,CHAR,ENUM,andSET.1)VARCHARisversatileforvariable-lengthstringsuptoaspecifiedlimit.2)TEXTisidealforlargetextstoragewithoutadefinedlength.3)CHARisfixed-length,suitableforconsistentdatalikecodes.4)ENUMenforcesdatainte

MySQLoffersvariousstringdatatypes:1)CHARforfixed-lengthstrings,2)VARCHARforvariable-lengthtext,3)BINARYandVARBINARYforbinarydata,4)BLOBandTEXTforlargedata,and5)ENUMandSETforcontrolledinput.Eachtypehasspecificusesandperformancecharacteristics,sochoose

TograntpermissionstonewMySQLusers,followthesesteps:1)AccessMySQLasauserwithsufficientprivileges,2)CreateanewuserwiththeCREATEUSERcommand,3)UsetheGRANTcommandtospecifypermissionslikeSELECT,INSERT,UPDATE,orALLPRIVILEGESonspecificdatabasesortables,and4)

ToaddusersinMySQLeffectivelyandsecurely,followthesesteps:1)UsetheCREATEUSERstatementtoaddanewuser,specifyingthehostandastrongpassword.2)GrantnecessaryprivilegesusingtheGRANTstatement,adheringtotheprincipleofleastprivilege.3)Implementsecuritymeasuresl

ToaddanewuserwithcomplexpermissionsinMySQL,followthesesteps:1)CreatetheuserwithCREATEUSER'newuser'@'localhost'IDENTIFIEDBY'password';.2)Grantreadaccesstoalltablesin'mydatabase'withGRANTSELECTONmydatabase.TO'newuser'@'localhost';.3)Grantwriteaccessto'

The string data types in MySQL include CHAR, VARCHAR, BINARY, VARBINARY, BLOB, and TEXT. The collations determine the comparison and sorting of strings. 1.CHAR is suitable for fixed-length strings, VARCHAR is suitable for variable-length strings. 2.BINARY and VARBINARY are used for binary data, and BLOB and TEXT are used for large object data. 3. Sorting rules such as utf8mb4_unicode_ci ignores upper and lower case and is suitable for user names; utf8mb4_bin is case sensitive and is suitable for fields that require precise comparison.

The best MySQLVARCHAR column length selection should be based on data analysis, consider future growth, evaluate performance impacts, and character set requirements. 1) Analyze the data to determine typical lengths; 2) Reserve future expansion space; 3) Pay attention to the impact of large lengths on performance; 4) Consider the impact of character sets on storage. Through these steps, the efficiency and scalability of the database can be optimized.


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