MySQL

MySQL added this utf8mb4 code after 5.5.3, Mb4 is the most bytes 4 meaning, specifically designed to be compatible with four-byte Unicode. Fortunately, UTF8MB4 is a superset of UTF8, except that there is no need to convert the encoding to UTF8MB4.

A simple summary innodb: support transactions such as No lock read support foreign key support row lock Index of fulltext type is not supported does not save the exact number of rows in the table, scans the table to calculate how

To manipulate the contents of a table by code:1. Add DataINSERT into Info values (' p009 ', ' Zhang San ', 1, ' n001 ', ' 2016-8-30 12:9:8 ');Add data to a specific columnInsert into Info (code,name) VALUES (' p010 ', ' John Doe ');Handling of

Use + database name: using this databaseCreating a data table unsgined means unsigned bit[IF not EXISTS] can be omittedCREATE table [IF not EXISTS] table (Usename VARCHAR (20),Age TINYINT unsgined)Show TABLES: See how many tables there are in the

Yesterday because the classmate's MySQL database did not know what to do, resulting in the root user can not use theIn particular, the use of root users do not need to enter the password can only see the Infomation_schema table, feel the root

Install and upgrade the required libraries with the Yum command that comes with the CentOS Linux systemLang=cYum-y install gcc gcc-c++ autoconf libjpeg libjpeg-devel libpng libpng-devel freetype freetype-devel libxml2 libxml2-deve L zlib zlib-devel

In general, this information exists in the tables table of the INFORMATION_SCHEMA databaseMysql>desc INFORMATION_SCHEMA. TABLES;+-----------------+---------------------+------+-----+---------+-------+| Field | Type | Null | Key | Default | Extra |+--

The two most commonly used engines in the Mysql database are Innordb and MyISAM. InnoDB is the default storage engine for MySQL. The difference between the two:1. Aspects of transaction processingMyISAM: The emphasis is on performance, which is

1.InnoDB Storage EngineInnoDB becomes the default storage engine in MySQL5.5 . InnoDB is a transactional storage engine designed to handle a large number of short-term transactions. Its performance and automatic crash recovery feature make it

My specific situation is: the use of robotframework test, could have passed a case error, the error is: Internalerror: (1205, U ' Lock wait timeout exceeded; try restarting Transaction　　Find the problem, that is, the online development environment

Reference Source: http://www.cnblogs.com/sshoub/p/4321640.htmlDirectoryI. OverviewSecond, MySQL installationThird, successful installation verificationI. OverviewMySQL version: 5.7.17: Http://rj.baidu.com/soft/detail/12585.html?aldClient Tools:

1. mysql Sub-database sub-table scheme 1.1. Question: 1.2. Answer: 1.2.1. The best way to divide MySQL is to not do it unless it is a last resort. 1.2.2. Your SQL statement is no longer declarative

In the installation of MySQL, there are cases where the original permissions cannot be deleted. After research, you need to manually remove permissions by following these steps.1. Start the MySQL service mysqld start2. Go to MySQL database, use

MySQL database sub-Library backup scriptversion 1For dbname in ' mysql-uroot-poldboy123-e ' show databases; "|grep-evi" database|informa|perfor "'Domysqldump-uroot-poldboy123--events-b $dbname |gzip >/opt/bak/${dbname}_bak.sql.gzDoneversion

Things go throughOne day, a sales C of our company's outer area said he could not find the workflow record for the previous August 3. Ask the reason, the original is updated number (our company's workflow is based on enterprise development). After

Turn from (http://www.cnblogs.com/iscodercn/p/5488633.html), there are supplementsFirst, install MySQL1. The installation needs to use the root account, if you do not set the root account, Google. In the process of installing MySQL, you need to set

Problem:Under normal user permissions to execute mysql-u root-p into the MySQL database, intermediate steps omitted, insert data: INSERT into library name (attribute) values (' Kanji ');The following prompt appears: Query OK, 1 row affected, 1

Mysql determines whether to insert data based on the conditions, and mysql inserts data based on the conditions. This problem is actually divided into two aspects: 1. Determine whether to insert data based on the table's primary key. 2. Determine

MySQL binlog data recovery, mysqlbinlog We have learned how to enable binlog of MySQL and the principles and common operations of binlog. We know that binlog has two major functions: Use binlog to restore data, the other is for master-slave

[Personal notes] Front-end mySql basics of zhitang, and mysql of zhitangAdd a column after it is specified: Alter table name ADD new column name int after specified ColumnFirst position: Alter table name ADD new column name varchar (20) AFTER