MySQL

Lamp Architecture IntroductionLamp is a shorthand that contains 4 things: Linux, Apache (httpd), MySQL, PHPLinux operating system, Apache provides WB service software, MySQL storage data software, PHP scripting languageHow Lamp worksThe browser

Scenario: MySQL adds a parent_id column to the table and sets it to not NULL, saving the Times wrong invalid use of NULL value.Cause of error: Because the parent_id of the existing data column is null, the setting conflicts with not NULL.Workaround:

ObjectiveInstalling MySQL database and navicat is not a difficult task, the key is how to make them work spent my whole day, and finally get it done. Encountered a variety of problems, the Internet to read a large number of blogs, found that many

PHP$DBI=NewDbmysql;$DBI->DBH = ' Mysql://root:[email protected]/coffeetest ';$map=Array();$DBI->fetchmap ("SHOW TABLES",$map);$tables=Array_keys($map); for($i= 0;$iCount($tables);$i++){ Echo($tables[$i]." \ n "); $sql= "SHOW INDEX

The company sent a question to me, the title is as follows:In the test database, there is a flow_user table that finds all records with the same character and greater than or equal to 2 in the email field. The final effect is as

1. Data typeWe've been talking about data types when we're learning PHP, so the data type is the format of the data. Each type of data stored in the computer will be different, the storage capacity is also different, so choosing the right data type

Recently found a very useful MySQL slow query log visualization tools, online can also find a lot of information, here combined with their own actual situation to reorganize.1. Experimental environment 1.1 system environment:操作系统：CentOS 6.5 64位主机地址：1

In the daily maintenance of the database, the developers are the most headache, many times due to the SQL statement written by the problem caused the server problems, resulting in resource exhaustion. The most dangerous operation is to forget the

Yesterday went to an interview, the company is not too big, is a Japanese-funded enterprises, in the domestic have several branches, the interviewer asked the basic operation and performance optimization of MySQL, said a lot, it is more relaxed, but

Objective Unlike most databases, MySQL has the concept of a storage engine that can choose the optimal storage engine for different storage requirements. 1. MySQL Storage Engine Overview Plug-in storage engine is one of the

By week  select Date_format (create_time, '%y%u ') weeks,count (Caseid) count from Tc_case Group by weeks;  Monthly   Select Date_format (create_time, '%y%m ') months,count (Caseid) count from Tc_case Group by months;   by day   Select Date_format

Or a cat's eye movie, for example, this time using Pyquery library to crawl 1. Simple demo, see How to extract information using pyquery, and combine the extracted data#Coding:utf-8#AUTHOR:HMKImportRequests fromPyqueryImportPyquery as

MySQL benchmark test (i)-reasons, strategies, ideas, reasons for using benchmark Verify some of the issues you think are verified by benchmarking and simulation data. Resolve some anomalies in the production system Test the current

SQL command Check of MySQL open-source database 1. Install wamp5.xxOpen the installation file in the compressed package and install it on the Windows2000 Server or Windows XPThe installation directory is tentatively set to D:/Wamp/**

Index is the most important tool for improving the query speed. Of course there are other technologies available for use, but in general, the biggest performance difference is the correct use of indexes. In the MySQL Mail List, people often ask for

I. Summary of the causes of MyISAM Table Corruption in MySQL: 1. The data file is damaged due to a sudden power failure on the server. The MySQL service is forcibly shut down without being shut down first. The mysqld process is killed when writing a

MySQL batch Import and Export Excel and TXT data 1. Excel files 1.1 export data to an Excel file select * into outfile "C:\\Users\\Administrator\\Desktop\\data_out.xls"from bi_admin; Note that the "\" contained in the storage path needs to be

Mysql is used in the recording project. During the test today, we found that the mysql database cannot be remotely connected. It turns out that mysql does not allow remote connection by default. After searching, we found a solution and recorded it

Mysql backup policies can be divided into four types: 1) directly copy database files (not recommended) 2) use mysqlhotcopy to back up the database 3) Use mysqldump to back up the database 4) use the master-slave replication mechanism (for real-time

Key Parameter Optimization Configuration of my. cnf (my. ini), my. cnfmy. ini MyISAM storage engine MyISAM storage engine is suitable for systems with high read performance requirements due to multiple reads and writes. Official documents: