MySQL

A transaction in MySQLThe InnoDB storage engine in 1.mysql does not support transactions.2. A transaction is a set of SQL statements that, as long as all the SQL statements succeed, the transaction commits (commit), and as long as one SQL statement

Problem: MySQL run after a few days to hang up, modify the number of MySQL connection can not solve, see the code is not a problem, but it is to feel which function has been the MySQL resources, check the current thread stateTime is the unit of

does not work for statistics count (type) and AVG (type)There are isnull methods in SQL, which are described as follows:ISNULLReplaces NULL with the specified replacement value.GrammarISNULL (Check_expression,

MySQL data definition statement is mainly to create, modify, delete the table, add, modify, delete the operation of the fieldTo create a table:CREATE Table Table name (property name data type constraint condition,Property name data type constraint

Although the statements for SQL Server and my SQL are basically consistent, there are still some minor differences. As with string connections, string connections in SQL Server are connected using "+", without the quotation marks SQL Server is

1. Create a tableCREATE TABLE [notnull][notnull],);Example:CREATE TABLE Student (Sno Char (7) NOT null primary key,Sname varchar (TEN) is not NULL,Ssex char (2),Sage integer)Data type char (fixed-length character): a space is usually used to

The benefits of using MySQL master-slave replication are:1, the use of master-slave server This architecture, stability can be improved. If the primary server fails, we can use the slave server to provide the service.2, processing the user's request

Error message: Java.sql.SQLException:Access denied for user ' root ' @ ' localhost ' (using Password:yes) 'AndIf you forget the root user password for MySQL, you can do the following ( Linux):If MySQL is running, first kill it: Killall-term mysqld.

Local:1. Go to the Bin folder in the MySQL directory: e: Enter;E:\>CD Mysql\bin? Enter2. Export database: Mysqldump-u user name-p database name > exported file nameExample: Mysqldump-u root-p ABC > ABC. SQL (export database ABC to ABC. SQL file)

Deploy MySQL high-use cluster with mysql-mmm and MySQL master-slave synchronizationPublic configuration:Close IptablesDisable SELinuxConfigure the Yum source.Fixed IPCan communicate with each otherBoth run the database serviceOnly the default

Install server$ sudo apt-get install Mysql-serverInstall driver $ sudo apt-get install Libqt4-sql-mysql　　$ dpkg--list | grep mysqlII Libdbd-mysql-perl 4.020-1build2 PERL5 Database interface to the My SQL databaseii libmysqlclient18 5.5.47-0ubuntu0.12

1:mysql is the mode of C/s architecture and can log in with TCP/IP when logging in to MySQLThe first time you log in to MySQL, you can log in directly with MySQL without a password.You can log in directly.2: basic command after LoginAfter logging in

Installation article: After the download is complete, unzip the tool into a folder without Chinese, blank space, the extracted display Personal suggestions to rename the unpacked folder, if there is Chinese remove Chinese, easy to

Master and slave failed to first view from the database show slave status\gRemember Bin-log Pos and Binlog files (typically select the last point of the nearest POS to recover) or view MySQL's error diary at a point in time,Convert Mysql-binlog to

1. Select the most applicable field propertiesMySQL is good at supporting large data volumes, but in general, the smaller the tables in the database, the faster queries are executed on it. Therefore, in order to achieve better performance when

#!/bin/bashI=1;max_insert_row_count=$1;While [$i-le $MAX _insert_row_count]DoMysql-uroot-proot dbname-e "INSERT INTO TableName (name,age,createtime) VALUES (' hello$i ', $i% 99,now ());"d=$ (date +%m-%d\%h\:%m\:%s)echo "INSERT HELLO $i @@

MySQL data is exported in a very large number of ways, such as mysqldump, mysql-e ' sql ' > file, which can be very convenient to export data, but when the use of ordinary users to export data, there is a problem. 1 Select * into

Two points need to be resolved, the configuration of the data source is given to spring, and transaction management is managed by a spring.//load file //start transaction as annotation

About the Next-Key lock and innodbnext-key of InnoDB Recently, I was preparing materials for new employee training. I was planning to introduce the concept. But since I have written the transaction chapter, I would like to introduce the lock and the

InnoDB WAL learning and InnoDBWAL Learning I wrote a blog post titled bad MySQL process writing habits (http://www.cnblogs.com/wingsless/p/5041838.html ). This blog post emphasizes that you do not need to submit transactions cyclically. Try to