MySQL

SQL optimization suggestion Memorandum 1. SQL comments generally do not increase performance overhead, and can enhance readability 2. The transaction should be brief www.2cto.com 3. Avoid cursor operations because the cursor occupies a large amount

After MySQL deletes data, id starts from 1. Usage: create table test (id int unsigned not null primary key AUTO_INCREMENT, username VARCHAR (15) not null) AUTO_INCREMENT = 100; www.2cto.com is used in database applications. We often use unique

Mysql trigger new old details mysql trigger new old: www.2cto.com "NEW. column_name "or" OLD. column_name ". in this way, it is technically processed (NEW | OLD. column_name) the New and Old column names belong to the created transition variable

How to view mysql connection parameters 1. view the details of all current connections :. /mysqladmin-uadmin-p-h10.140.1.1 processlist www.2cto.com 2. view only the current number of connections (Threads is the number of connections .) :.

The float and decimal float and double types in MySQL are prone to errors. When the precision requirements are relatively high, we recommend that you use decimal for storage. decimal is stored in mysql memory as strings, it is used to define data

MYSQL5.5 Master/Slave configuration: A-> B-> c a (Port 3307)-> B (Port 3308)-> C (Port 3309) I. configuration file www.2cto.com A (my. cnf): # configure a unique ID: server-id = 1 # enable binlog-bin log_slave_updates binlog_format = row # configure

MySQL 1594 error solution MySQL 1594 error solution: Example: www.2cto.com Master_Log_File: mysqld-bin.000042 Read_Master_Log_Pos: 99749808 Relay_Log_File: mysqld-relay-bin.000083 Relay_Log_Pos: 15995 runtime: mysqld-bin.000041 runtime: Yes Slave_

Summary 1. method 1: run the mysqladmin command. It is applicable to remembering the old root password. Modify the root password Syntax: www.2cto.com mysqladmin-u username-p old password new password. Example: # mysqladmin-u root-proot password

The methods for changing the root password in MySQL are as follows! Www.2cto.com Method 1: use the set password command mysql-u root mysql> set password for 'root' @ 'localhost' = PASSWORD ('newpass'); Method 2: use mysqladmin-u root password

Solve the problem of slow login to intranet ssh/mysql. The company's development environment will be deployed on the Intranet. Then there will be a public server for everyone to develop and test on, so there will often be ssh connection to the

MySql modifies the encoding and character set to enter the database installation directory: C:/Program Files/MySQL Server 5.0. find The INI file at www.2cto.com client section # -------------------------------------------------------------------- #

To solve the problem that other MySQL machines cannot connect to mysql, we recently encountered various problems during MySQL configuration. Let's summarize them. After installing www.2cto.com mysql, the local machine can be connected, but other

Example of using find_in_set in Mysql: a field (purview) in the user table indicates the user's permission to save all the user's permission IDs to this field. For example, the following five permissions are available: 1, 2, 3, 4, and 5: select *

The MySQL database lock mechanism is called a lock. To ensure data consistency, it is a rule that allows concurrent access to shared resources to become orderly. Different MySQL storage engines have different lock mechanisms or lock implementations.

I recently graduated from a windows mysql database to a linux database. I need to port mysql under windows to linux. I have had the experience of porting mysql databases under windows, you only need to copy the data file of msql to the data storage

How does MySQL modify the character set of a table and the character set of a field? If you want to change the character set of the table's default character set and all character columns to a new one, use the following statement: alter table

REDO parsing in innodb is implemented in the innodb Storage engine. Transaction logs are implemented by redo log files and innodb log buffer of the innodb Storage engine. When a transaction starts, an LSN (Log sequence number) of the transaction is

EXPLAIN for query optimization different SQL statement writing methods often lead to great performance differences. How can we know the SQL query execution overhead? MySQL provides the EXPLAIN keyword for us. When you add the EXPLAIN keyword before

[Architecture] MySQL Log File-slow query log as the name suggests, in the slow query log, a threshold value can be set for a query with a long execution time. All SQL statements whose running time exceeds the threshold value are recorded in the slow

Mysql5.6.10 about the slow query settings slow-query-log two days ago, I just upgraded the development environment to 2008R2, so I want to try a 64-bit database of 5.6.10, it is the win32x64 version officially downloaded from mysql, with a total of