MySQL

MySQL data typeThe type of data field defined in MySQL is important for optimizing your database.MySQL supports multiple types and can be broadly divided into three categories: numeric, date/time, and string (character) types. Numeric

MySQL Create data tableThe following information is required to create a MySQL data table: Table name table field Name Define each table field GrammarThe following is the general SQL syntax for creating MySQL data

ERROR 1046 (3d000): No Database selectedError Explanation: No database selected---- Reason: The corresponding database was not opened (creating tables and operations on tables need to be performed under the database)---- Resolution: Open database:

1, high version of MySQL (5.5), the stored procedure limit can use variables, as follows: SELECT * from student limit istart,inum;2, the low version of MySQL (5.1), stored in the process of limit can not use variables, compile error, as follows: You

MySQL Meta DataYou may want to know the following three kinds of information about MySQL: Query Result information: The number of records affected by the SELECT, UPDATE, or DELETE statement. Database and data table information: contains

The MySQL master and slave feature is set on CentOS 6.5 and recorded.Test environment set up, hope to help everyone.Server 1 (primary)ip:192.168.1.201System version: CentOS 6.5MySQL version: MySQL 5.5Server 2 (from)ip:192.168.1.202System version:

Time Type:1.5 time types are supported in MySQL, namely date, hour, DATETIME, timestamp, and year.In the daily build table we want to use the timestamp type first, it has the function of automatic update time, example:You can also set not to update

　　One, MySQL database backup commandMySQL database using command Line BackupFor example:Database address: 127.0.0.1Database user name: rootDatabase Password: PassDatabase name: MyWebBack up database to D disk and

A. PrepareSystem: ubuntu 14.04.2 LTSMysql:server version 5.5.43two hosts can communicate with one another: 192.168.1.11 Master192.168.1.12 slavetwo. StepsMaster section:1. Create a backup account: slave Password: slaveGrant replication

Database query Optimization There are many things you can do. Here's a summary of some:Basic principles: Reduce the number of disk I/Os that occur during database queries Rational use of indexes Avoid full table traversal,

ORDER by Optimization In some cases, MySQL can use the index sort to avoid extra sorting.Even if the ORDER BY statement column does not match index exactly, as long as there are no columns in index (not in the order by), the where statement appears

1. Design principles 1) Standardization and normalizationStandardization of data helps eliminate data redundancy in the database. There are several forms of normalization, but the third normal form (3NF) is generally considered to be the best

1. Date converted to the specified format: date_format (date, format)2, int type time converted to the specified format: from_unixtime (Unix_timestamp,format)Format the date value according to the format string:%s,%s two digits in seconds (00, 01, ..

mysql version number MySQL Ver 14.14 distrib 5.1.73, for Redhat-linux-gnu (x86_64) using ReadLine 5.1 system is centos6.5The problem is: Mysql-u Enter a non-existent user can log in to the databasethe data in the Mysql.user library is:mysql> Select

There are two ways to install MySQL on Mac platforms:1) Use the official DMG installation;2) Use homebrew modeI recommend the use of homebrew way to install, save most of the trouble, the use of official DMG method recommended to the official

Yesterday in the test run the environment to do the system upgrade, suddenly SSH connection disconnect, try to connect always error, and then restart my computer to connect again, still error, strange test personnel visit the company's Liferay

Forget the root password of the original myql;First, you must have root access to the operating system. If you do not have the root authority of the system, consider the root system before taking the following steps.Similar to Safe Mode login system,

Install mysql 1 with Yum under Linux, install to see if you have installed:          Yum list installed mysql*      &NB Sp   RPM-QA | grep mysql*  See if there are no installation packages:          Yum list mysql*  install MySQL client:        &

Create a simple tutorial for creating a MySQL database Use mysqladmin to create a database: Special permissions are required to create or delete a MySQL database. Therefore, if you access the database as a root user, you can create any database

Mysql paging negative SQL attack1. Attack Analysis CleverCode's O & M colleague told me that when he checked the mysql error log, he found a large number of errors, so someone was attacking a specific address. This error occurs because mysql does