MySQL

My friend seaside asked me what is the length of the int type when I build the table in MySQL? Is this column allowed to store the maximum width of a value? Why I set it to int (1), also can save 10,100,1000.While I knew Int (1), this length of 1

recently, when learning the configuration of a MySQL cluster, first understand what cluster, why to use the cluster, and what software to install the cluster is and what processes are in the cluster. 1. What is a cluster? A cluster is a group of

1. Cause Analysis of table damageThe following reasons are common causes of MySQL table corruption:1, the server suddenly power loss caused data file corruption.2, forced shutdown, did not first shut down the MySQL service.3. The mysqld process is

MySQL study--mysql Ordinary users cannot log on locallyAfter the installation has completed MySQL, we usually add a regular user with the appropriate permissions to access the database. When using the user to log in to the database, often there is

Related commands on the primary server:Show master status;Mysql>Show Master Status\g*************************** 1. Row*************************** File: Host2-Bin.000002Position:420binlog_do_db:binlog_ignore_db:executed_gtid_set:5abd564e-2

mysql> use Qq;database changedmysql> #查询本店价比市场价省的钱, and ask to save more than 200 yuan to remove to mysql> select Goods_id,market_price,shop _price, (Market_price-shop_price) as discount from goods where has discount>200; Error 1064 (42000): You

Http://www.cnblogs.com/hongten/p/java_poi_excel.htmlThis blog is an introduction to the POI technology in Java to read Excel data and then save it to MySQL data.You can also read and import excel in: Java's POI technology to learn how to write Excel

I do not know why, the newly installed MySQL, if you try to log in with Mysql-u root-p This error will occur, but the root user did not set the password.ERROR 1045 (28000): Access denied for user ' root ' @ ' localhost ' (using Password:no)Here's

To import *.sql scripts directly in MySQL Qurey Brower, is the command to execute SQL files in MySQL without executing multiple SQL commands at once:Mysql> source D:/myprogram/database/db.sql;Also attached to MySQL common commands:A) connect to

int: An int type of 4 bytes in SQL with a length of 1 represents the length of an int type Symbol-Differentiated range: 2147483647~-2147483648 VARCHAR: A varchar type can contain a number, letter, kanji, such as a field of length 15 can hold 15

There was a problem when the data source configuration was added with the Encoding conversion format:The reference to entity "characterencoding" must end with the '; ' delimiterThis error is the problem of setting the URL of the data source link in

Master-slave replication is asynchronous and can be used by one of Google's plugins to achieve semi-synchronouse.1 Master-slave replication principle650) this.width=650; "style=" WIDTH:700PX;HEIGHT:427PX; "src=" http://s3.51cto.com/wyfs02/M00/6F/98/

Original link: http://jingyan.baidu.com/article/f3ad7d0ffc061a09c3345bf0.html?qq-pf-to=pcqq.c2cMySQL is a small but powerful database, which is very popular at present. However, the official website gives the installation package in two formats, one

Reprint Please specify source: http://blog.csdn.net/l1028386804/article/details/46763665A trigger is a special stored procedure, in which the stored procedure is called with call, and the trigger does not need to use the callingIt does not need to

Drbd+heartbeat+mysql: Configuring High Availability for MysqlDescriptionToday, the second application of DRBD, using drbd+heartbeat+mysql: Configuring Mysql's High AvailabilityEnvironment:[Email protected] ~]# Cat/etc/issuecentos release 6.4 (Final)

Comparison of datetime and timestamp in the original address Http://database.51cto.com/art/200905/124240.htmMySQLThis article compares the datetime and timestamp in MySQL with an example, although these two methods actually represent the same type,

This time when using the MySQL database to find a problem. If it's another computer on a local area network using the SQLyog tool to connect to the MySQL database, there will be no connectivity issuesThe way to resolve: Log in as user root

DELIMITER &&CREATE PROCEDURE Syncadvertiser ()BEGINDECLARE ID bigint;DECLARE _cur CURSOR for SELECT ID from advertisers;OPEN _cur;REPEATFETCH _cur into ID;SqlUNTIL 1>0 END REPEAT;CLOSE _cur;END;DELIMITER;DELIMITER && and DELIMITER should be noted ;

Demand:Add a field to a table in a database (if the field already exists, do not do so; if the field does not exist, the new one)Baidu has been n long, did not meet the requirements of the example, only the reference to add their own pondering,

MySQL in the use of the process encountered slow access, or can not respond to such problems, the solution is basically a formula, the general first reaction will be logged in to MySQL, show processlist see the current connection status.Although