MySQL

Backup command:- - -- Default-character-set=utf8--hex-blob-r--log-error=/var/log/backup-log--single-transaction-b ccjf_data > Ccjf_data_20151022.sql--Default-character-set=utf8--hex-blob-r--master-data--log-error=/var/

Steps:1. Turn on transaction start transactionWhen we start a transaction, our operations on SQL occur in memory, but there is no real feedback to the files in the database disk!2. Rollback rollbackRollback is the most primitive state to revert to

MySQL Tens data table, creating table and field extensions for several suggestionsOne: OverviewWhen we design a system, we need to consider the system after a period of time, the table data volume about how much, if in the early days, it can be

about MySQL database optimizationIn my humble opinion, the database is optimized to optimize storage and query speedAt present the main optimization I think is to optimize the query speed, query speed, improve the user's experienceI think that the

DATABASE ()Returns the current database nameBENCHMARK (count,expr) repeatedly runs the expression expr count timesCONNECTION_ID () Returns the connection ID of the current customerFound_rows () returns the total number of rows retrieved by the last

ASCII (char) returns the ASCII code value of a characterBit_length (str) returns the bit length of a stringCONCAT (S1,S2...,SN) to concatenate s1,s2...,sn into a stringConcat_ws (SEP,S1,S2...,SN) joins the S1,S2...,SN into a string and uses the Sep

Sometimes MySQL can not completely uninstall, this time must be removed by some means of the registry and some residual files, and then can be re-installed to succeed!1. Control Panel--"All Control Panel items--" program and function, uninstall

javax.jdo.option.connectionurljdbc:mysql://server110 :3306/hive?createdatabaseifnotexist=truejavax.jdo.option.connectiondrivernamecom.mysql.jdbc.driverjavax.jdo.option.connectionusernamerootjavax.jdo.option.connectionpasswordrootHive-site.xml

MySQL has 4 functions for conditional operation, which can implement the conditional logic of SQL, allowing the developer to transform some application business logic into the database background.MySQL Control flow function:Case When[test1] then

Java Web Query, gender word Gencun is the number, 1 for male, 2 for female, take the data when the gender into Chinese characters displayed on the page, the SQL statement as follows, the result has been a problemSelect A.emp_id,a.emp_name, case when

It's a good idea to use the merge storage engine middleware to implement MySQL sub-table.Can look at this blog written very clearly--http://www.cnblogs.com/xbq8080/p/6628034.htmlIn addition, the use of triggers is as follows:1 ## MySQL Trigger2 3 T1

Limit in MySQL can achieve fast paging, but if the data to millions of when our limit must be optimized to effectively achieve a reasonable paging, or may be stuck to your server. When there are millions of data in a data table, it's a problem!For

MySQL database in Linux system is case-sensitive by defaultToday in development encountered such a problem, the connection to the database to the server (the server is a Linux system), the program has been running out of error, the total hint of the

Objective1. mysql InstallationCentOS 7 's Yum source does not appear to be properly installed when MySQL mysql-sever file, need to go to the official web download # wget http://dev.mysql.com/get/mysql-community-release-el7-5.noarch.rpm# RPM-IVH

Ubuntu Server mysql5.9The Enable function edits the MySQL configuration file on the master and slave server separately#vim/ETC/MYSQL/MYSQL.CONF.D/MYSQLD.CNF Add the following two linesbind-address = 0.0.0.0 #修改为允许任意服务器访问Log-bin=mysqlServer-id=1

InnoDB supports transactional features, MyISAM not supported.Myisam executes faster and performs better.2, select, UPDATE, INSERT, delete operationMyISAM: If performing a large number of select,myisam is a better choice InnoDB: If your data performs

Standalone index:A stand-alone index refers to an indexed column that cannot be part of an expression, or a function's argument　　Example 1:SELECT actor_id from actor where actor_id+1=5-this notation, even if indexed on actor_id, is not

To view the database character set:Show database Create dbname \g;To view the database table character set:Show table Create Tbname \g;To view the existing database character set settings:Show variables like ' character_set% ';To temporarily modify

Add, delete, modify, and query mysql Databases Try{// Insert new user information into the databaseString strsql = "insert into httang_test.test (id, name, password, adress) values ('" + this. idTextBox. text + "','" + this. nameTextBox. text + "','"

Mysql Case sensitivityProblem: When you create a mysql table, whether it is in upper or lower case, it is changed to lower case after the table is created.Cause: MySQL is case-insensitive in windows. After the script file is imported into MySQL,