MySQL

int type includes (tinyint, smallint, mediumint, int, bigint) Tinyint is a 1 byte expression range of 2 8 (-128-128) or (0-255) Many people do not understand why there are two cases, because in the computer there is a statement called unsigned,

This paper discusses the idea of improving the performance of MySQL database, and gives the concrete solution from 8 aspects.1. Select the most applicable field propertiesMySQL is good at supporting large data volumes, but in general, the smaller

Haven't written blog for a long time, write a simple thing warm warm up, share to everybody.JDBC believes that everyone is not unfamiliar, as long as it is a Java, the initial contact with the EE time is to learn such a thing, who called the program

Note: All operations in this document operate with the following conditions,A, the remote Linux server has installed MySQL databaseB, local computer can ping remote serverC, the MyEclipse has been successfully installedFirst, download

Explain select a.* from test A, (SELECT ID from test where level_id Because the deferred association returns the primary key of the desired data row by overwriting the index, then the primary key is associated with the original table to obtain the

Mysql InnoDB Line Lock Implementation method innodb row locks are implemented by locking the index entries on the index, which is different from Oracle, which is achieved by locking the corresponding data rows in the data block. InnoDB This type of

MySQL log management and MySQL backup restore under Linux1.SHOW GLOBAL VARIABLES like '%log% '; Show all log-related options2. Error log: Log_error and Log_warnings3. General Enquiry log: General_log general_log_file log Log_output4. Slow query log:

1. Installation dependent (operation only on Master side)Yum-y Install Mysql-python2. Create the corresponding table structure in the master side local databasecreate database   ' Salt '   default character set utf8  default  COLLATE utf8_general_ci;

Problem Description: Java.sql.SQLException:Incorrect string value: ' \XF0\X9F\X90\XBB ' for column ' nickname ' at row 1        at Com.mysql.jdbc.SQLError.createSQLException (sqlerror.java:1094)         at Com.mysql.jdbc.MysqlIO.checkErrorPacket

The same website program runs under Linux much faster than under Windows, so decided to use the Linux distribution version of CentOS , this article mainly explains the use of the Yum command to install lamp details under CentOS. The software we use

Troubleshoot database no connection issues PrefaceDatabase version type: Mysql5.5The database connection failed when the application connected to the database. Open database view, shown below.The reason for this is that the MySQL service is having

0. The difference between the primary key and the indexThe primary key has only two uses on the physical level: uniquely identifies a row, and as an object that can be effectively referenced by a foreign key.An index is a special kind of file (an

Background Introduction mysql5.5 previous version, MySQL master-slave replication is relatively simple    Mysql5.6:gtid,multi-thread replicationMaster1 Enable binary Log log-bin = Master-binlog-bin-index = Master-bin.index2 Select a unique server

DROP TABLE IF EXISTS ' order_seq ';CREATE TABLE ' Order_seq ' (' Timestr ' int (one) is not NULL,' ORDER_SN ' int (one) not NULL) Engine=innodb DEFAULT Charset=utf8;DROP FUNCTION Order_seq;Create function Order_seq ()Returns integerBegindeclare

Source: A braised eggbackground:One of their own site, because the single-table data record up to 1 million, resulting in slow data access, the background of Google Analytics often report timeouts, especially pages with large page is slow.test

Binary installation of the database may have garbled problems, the compiled installation of the database specified by default utf-8 does not produce garbled1. Compile the installed character set conditionView the format of a character set

System version: OS X El CapitanMySQL version: MySQL Community Server(GPL) (MYSQL-5.7.13-OSX10.11-X86_64.DMG)/* Website download installation, brew seems to support, next try * *1. Open DMG installation pkg, installation should have a notification

In a transaction, each correct atomic operation is executed sequentially until an incorrect atomic operation is encountered, at which point the transaction rolls back the previous operation. Rollback means that if a previous insert operation is

1, the general situation needs to be qt5core.dll,qt5gui.dll,qt5sql.dll,qt5widgets.dll,platforms\qwindows.dllMsvcp120.dll,msvcp120.dll (I'm using the VS2013 version of Qt5.5)Plugins\sqldrivers\qsqlmysql.dll (sometimes you need to recompile this file,

MySQL replication table structure, mysql replication StructureIntroduction Sometimes we need to copy the table structure of a table intact to generate a new table. MYSQL provides two convenient methods.   Example: CREATE TABLE tb_base(id INT NOT