MySQL

When mysql modifies an index, the foreign key constraint causes a strange problem. In mysql5.5 of Windows, I want to modify the index of a table, run www.2cto.com [SQL] ALTER TABLE practice_log DROP INDEX ix_practice_log_userid; ALTER TABLE practice_

In the MySQL master-slave environment, we can run show slave status on slave to view some slave status information. Among them, there is an important parameter Seconds_Behind_Master. Do you understand the true meaning of it and how it is

6 frequently-used MySQL queries use structured query languages to develop correct and effective database questions and commands to query architectural art. In a SELECT query, you can use JOIN, WHERE, and HAVING clauses to analyze and summarize

MYSQL creates a database in UTF-8 format first mysql enters: www.2cto.com Linux code GBK: create DATABASE test2 default character set gbk COLLATE gbk_chinese_ci; UTF8: CREATE database 'test2' default character set utf8 COLLATE utf8_general_ci; eg:

In database design, for a specific project, the same table prefix is usually specified for all data tables, for example, WordPress Data Tables start with wp _ and Discuz Data Tables start with dz. This not only facilitates differentiation, but also

For the question about why limit is slow in the future, we have used mysql paging, the implementation is generally select * from talbe_name limit pageSize * (pageNo-1), pageSize the first few pages of the statement is very fast, why does pageNo

Mysql exists subquery can be divided into: from where and exists subquery www.2cto.com classification table: [SQL] mysql> select * from category; + ---- + --------- + | id | c_name | + ---- + --------- + | 1 | ios | 2 | android | 3 | sb | + ---- + --

Detailed analysis of MySQL limit usage when we use related query statements, we generally need to return the first few or a few rows of data in the middle. What should you do? Don't worry, MySQL database already provides us with such a function. The

"MySQL" Multi-table field matching 1 $ SQL = $ empire-> query ("select table. title, lianxi, table. dizhi, table. id from table, table1 where table1.sid like concat ('% |', table. id, '| %') and table1.id = ". $ navinfor [id]. ""); 2 while ($ r = $

The meaning of four timeout parameters in MYSQL 4 timeout is used to prevent a link from occupying the descriptor of a database for a long time. If there is a problem with the network, the descriptor is not released, thread blocking is a waste of

MySQL index details index is a special file (index on the InnoDB data table is a part of the tablespace), which contains reference pointers to all records in the data table. Www.2cto.com Note: [1] indexing is not omnipotent! Indexing speeds up data

Mysql inserts large data into a table. Method 1: The data volume is not large and there are thousands of rows of data. use notepad to edit the data. The result is as follows: insert into 'web4399 _ vote '. 'frxz2 _ hlwjhj_code '(active_code) values (

Solve the 1093 error in modifying table records in mysql. requirement: known TABLE information: TABLE Name: frjg TABLE structure: [SQL] DROP TABLE IF EXISTS 'frjg'; CREATE TABLE IF NOT EXISTS 'frjg' ('id' int (11) not null AUTO_INCREMENT, 'jgbh'

In Windows, MySQL executes SQL script files in batches recently for database migration. It is too difficult to manually execute MySQL script files in batches, so I wrote a script to share it. 01 @ echo off02: Specify the MySQL installation path 03D:

Mysql's FIND_IN_SET () usage FIND_IN_SET (str, strlist) returns the serial number of str in the strlist of the string set (if any parameter is NULL, NULL is returned. If str is not found, 0 is returned, an exception occurs when parameter 1 contains "

Build a mysql cluster in linuxChapter 2 Environment Description1.1 System DescriptionThree linux servers are used and centos is used to minimize the installation of the system.1.2 Software DescriptionDatabase Management Nodes and database nodes all

Emma Chinese display garbled problem solved in Linux if you use the mysql graphics client, I personally feel that Emma is not bad. However, if emma is installed with apt-get by default, emma does not support Chinese characters. You need to modify

Location of the Code involved in the MySQL main process 1. main () in SQL/mysqld. cc 2. the function for receiving the request is: handle_connetions_sockets (), SQL/mysqld. cc 3. request Processing Portal: handle_one_connection (), SQL/SQL _parse.cc

On the official website of non-installed mysql 5.5, the windows Installation version is available. mysqld is automatically configured as the startup service. Although it is very convenient, it is not very clear and does not help you learn mysql,

Ubuntu installation and configuration mysql this article only introduces the simplest and most basic installation and configuration methods 1. install [plain] sudo apt-get install mysql-server during installation, the mysql password is set interface,