MySQL

http://blog.csdn.net/qsc0624/article/details/51335632It should be known that the InnoDB Single-column index cannot exceed 767bytes, and a federated index has a limit of not more than 3072 length. mysql> CREATE TABLE ' TB ' ( -A ' a '

Mysqli:query ($strsql); Loop out the record while ($row =mysqli_fetch_assoc ($result)) { $status = $row [' status ']; $scookies = $row [' scookies ']; } Release Resources $result->close (); Close connection $db

Grammar:CREATE table (Field name 1, data type [constraint],Field Name 2, data type [constraint],....)Example:mysql> CREATE TABLE TB_EMP1(ID INT (11),Name VARCHAR (25),-DeptID INT (11),-Salary FLOAT);Mysql> desc tb_emp1;+--------+-------------+------+

/*Defining variablesMode 1:set @ variable name = value;Mode 2:select value into @ variable name;Method 3:declare The default value of the variable name type (string type plus range);The value of the in parameter entry will only work in the stored

1) Sub-tableObjective: To improve the efficiency of the access operation of massive dataSelect the appropriate sub-table strategy, determine the sub-table strategy, when the data access operations, the requirements are determined to go to that table

MySQL input decimal number automatically become an integer, lost half a day do not know how.The type of field in the database is obviously set to a decimal type such as Double,float, but when you enter a decimal number, the decimal number becomes an

After the MySQL database service is configured, the system will have 4 default databases.Information_schema: Virtual objects, whose objects are stored in memoryPerformance_schema: Server Performance Metrics LibraryMySQL: Log user permissions, Help,

Read Catalogue 1. Avoid creating database and table garbled and view encoding method 2. Avoid the problem of importing data with Chinese characters 3. Solve the problem of garbled pages MySQL will appear in Chinese garbled

Copyright notice: Transfer from:http://www.linuxidc.com/Linux/2015-08/121667.htmDescription:CentOS 6.6 Under source code compilation install MySQL 5.7.51. Installing related tools# yum-y Install gcc-c++ ncurses-devel cmake make perl \GCC autoconf

For slow SQL Analysis steps: 1) Desc|explain SQL view execution plan, for type very slow, analysis whether to establish the corresponding field index 2) to exclude the method, the query extraction out, separate execution, positioning slow query is

MySQL provides replication functionality starting from 3.23, which means that the DDL and DML operations of the main library are routed through the Binlog file to be executed from the library, keeping the main library and synchronizing the data from

Share a MySQL sub-library backup script (original)Development ideas:1. Path: Specify the location of the backup, the path (the first to determine whether there is no creation of a directory) first defined, my path:/mysql/backup, each backup with

Chapter II Introduction to MySQL data types· first section: integer type, floating-point type, and fixed-point number typeIntegral type:· TinyInt (1 bytes)· SmallInt (2 bytes)· mediumint (3 bytes)· Int and Integer (4 bytes ) · BigInt (8

JDBC tool and javajdbc ToolDatabase Connection toolkit under Util package 1 package util; 2 3 import java. SQL. connection; 4 import java. SQL. driverManager; 5 import java. SQL. resultSet; 6 import java. SQL. SQLException; 7 import java. SQL.

It perfectly solves the problem of disabling mysql immediately after it is started (the ibdata1 file is damaged) and mysqlibdata1 Mysql on a server in the data center has been running for a while, and suddenly a strange phenomenon occurs: it cannot

For more information, see mysqldump data export. 1. An error (1064) is reported when mysqldump is used. This is because the version of mysqldump is too low and is inconsistent with the current database version. Mysqldump: Couldn't execute 'set

The latest installation tutorial for mysql 5.7.17 is illustrated in the text. Mysql-5.7.17-winx64 is now the latest version of Mysql, which is free of installation, so some configuration is required : Https://cdn.mysql.com//Downloads/MySQL-5.7/mysql-

MySQL database transaction isolation level details, mysql details Database transaction isolation level There are four isolation levels for database transactions, from low to high Read uncommitted: Dirty Read is allowed. Read committed: it is

Mysql create routine permission description, mysqlroutine 1. If you have the create routine permission, you can create procedure | function. 2. If you create procedure | function, mysql automatically grants it the alter routine and execute

About MySQL innodb_autoinc_lock_mode, innodbstrictmode The innodb_autoinc_lock_mode parameter controls the behavior of locks when inserting data to a table in the auto_increment column; By setting it, you can achieve a balance between performance