1.查看Linux 是否安装了Mysql[root@localhost zhoulinghong]# rpm -qa |grep MySQL MySQL-server-community-5.1.22-0.rhel4已经安装了
1.查看Linux 是否安装了Mysql
[root@localhost zhoulinghong]# rpm -qa |grep MySQL
MySQL-server-community-5.1.22-0.rhel4
已经安装了。
2.Linux 下安装mysql(rpm)
[root@localhost zhoulinghong]# rpm -ivh MySQL-server-community-5.1.22-0.rhel4.i386.rpm
warning: MySQL-server-community-5.1.22-0.rhel4.i386.rpm: V3 DSA signature: NOKEY, key ID 5072e1f5
error: Failed dependencies:
perl(DBI) is needed by MySQL-server-community-5.1.22-0.rhel4.i386
Suggested resolutions:
perl-DBI-1.40-5.i386.rpm
呵呵,出错了。Linux的弊端就出现了。安装软件的时候相互依赖太强了。。。看到上面错误信息是缺少perl-DBI-1.40-5.i386.rpm包。没有办法只能安装了
3.安装依赖包
perl-DBI-1.40-5.i386.rpm 这个包在RedHat的CD2中。不用多想挂载光驱吧。
[root@localhost mnt]# mount /dev/cdrom /mnt/cdrom
挂载成功以后。转到 /mnt/cdrom/RedHat/RPMS目录下面就有perl-DBI-1.40-5.i386.rpm 这个包了。
[root@localhost RPMS]# rpm -ivh perl-DBI-1.40-5.i386.rpm
warning: perl-DBI-1.40-5.i386.rpm: V3 DSA signature: NOKEY, key ID db42a60e
Preparing... ########################################### [100%]
1:perl-DBI ########################################### [100%]
安装成功。
OK,到现在的依赖包也安装完了,,就可以安装mysql了。(注意:因为大家的环境不一样,中间可能有其他的依赖包需要安装,方法照上面就好了。)
4.安装Mysql
[root@localhost zhoulinghong]# rpm -ihv MySQL-server-community-5.1.22-0.rhel4.i386.rpm
warning: MySQL-server-community-5.1.22-0.rhel4.i386.rpm: V3 DSA signature: NOKEY, key ID 5072e1f5
Preparing... ########################################### [100%]
1:MySQL-server-community ########################################### [100%]
PLEASE REMEMBER TO SET A PASSWORD FOR THE MySQL root USER !
To do so, start the server, then issue the following commands:
/usr/bin/mysqladmin -u root password 'new-password'
/usr/bin/mysqladmin -u root -h localhost.localdomain password 'new-password'
See the manual for more instructions.
Please report any problems with the /usr/bin/mysqlbug script!
The latest information about MySQL is available on the web at
Support MySQL by buying support/licenses at
Notes regarding SELinux on this platform:
=========================================
The default policy might cause server startup to fail because it is
not allowed to access critical files. In this case, please update
your installation.
The default policy might also cause inavailability of SSL related
features because the server is not allowed to access /dev/random
and /dev/urandom. If this is a problem, please do the following:
1) install selinux-policy-targeted-sources from your OS vendor
2) add the following two lines to /etc/selinux/targeted/src/policy/domains/program/mysqld.te:
allow mysqld_t random_device_t:chr_file read;
allow mysqld_t urandom_device_t:chr_file read;
3) cd to /etc/selinux/targeted/src/policy and issue the following command:
make load
Starting MySQL[ OK ]
Giving mysqld 2 seconds to start
很明显,安装成功了。如果安装失败了就卸载一次在安装一下就基本没有什么问题了。

mySqlStringTypesimpactStorageAndPerformanCeaseAsfollows:1)长度,始终使用theSamestoragespace,whatcanbefasterbutlessspace-felfficity.2)varCharisvariable varcharisvariable length,morespace-morespace-morespace-effficitybuteftife buteftife butfority butfority textifforlyslower.3)

mySqlStringTypesIncludeVarChar,文本,char,enum和set.1)varCharisVersAtileForvariable-lengthStringStringSuptOptoPeptoPepecifientlimit.2)textisidealforlargetStortStorStoverStorextorewiteWithoutAdefinedLengthl.3)charlisfixed-Length

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)

toadduserInmysqleffectection andsecrely,theTheSepsps:1)USEtheCreateuserStattoDaneWuser,指定thehostandastrongpassword.2)GrantNectalRevileSaryPrivilegesSustate,usiveleanttatement,AdheringTotheTeprinciplelastPrevilegege.3)

toaddanewuserwithcomplexpermissionsinmysql,loldtheSesteps:1)创建eTheEserWithCreateuser'newuser'newuser'@''localhost'Indedify'pa ssword';。2)GrantreadAccesstoalltablesin'mydatabase'withGrantSelectOnMyDatabase.to'newuser'@'localhost';。3)GrantWriteAccessto'

MySQL中的字符串数据类型包括CHAR、VARCHAR、BINARY、VARBINARY、BLOB、TEXT,排序规则(Collations)决定了字符串的比较和排序方式。1.CHAR适合固定长度字符串,VARCHAR适合可变长度字符串。2.BINARY和VARBINARY用于二进制数据,BLOB和TEXT用于大对象数据。3.排序规则如utf8mb4_unicode_ci忽略大小写,适合用户名;utf8mb4_bin区分大小写,适合需要精确比较的字段。

最佳的MySQLVARCHAR列长度选择应基于数据分析、考虑未来增长、评估性能影响及字符集需求。1)分析数据以确定典型长度;2)预留未来扩展空间;3)注意大长度对性能的影响;4)考虑字符集对存储的影响。通过这些步骤,可以优化数据库的效率和扩展性。


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