MySQL

1) READ UNCOMMITTED: Read data that has not yet been committed: no problem is solved2) Read Committed: Reads the data that has been submitted: can resolve dirty read----Oracle Default3) Repeatable READ: Reread read: Can resolve dirty read and

I. Creating a Database# # #语法:# # #create database or CREATE schema# # #create Database or schema if not EXISTS DB name###[Specifies the default value]character set sets the character set GBK Simplified Chinese UTF8 Universal Code BIG5 Traditional

First, MySQL Replace usage1.replace intoReplace into table (Id,name) VALUES (' 1 ', ' AA '), (' 2 ', ' BB ')The purpose of this statement is to insert two records into table tables. If the primary key ID is 1 or 2 does not existis equivalent

:Select sum( Case Month(Createtime) when '1' Then 1 Else 0 End) asJanuary,sum( Case Month(Createtime) when '2' Then 1 Else 0 End) asFebruary,sum( Case Month(Createtime) when '3' Then 1 Else 0 End) asMarch,sum( Case Month(Createtime) when '4'

When MySQL forgets the password, the following steps are enforced:　1. Edit the configuration file with the command /etc/my.cnf　　　　2. Add a statement to make it into a state without a password skip-grant-tables　　3. Save and exit, then command line

MVCC is a variant of a row-level lock, but it avoids lock-up operations in many cases and therefore costs less. MySQL, including Oracle, PostgreSQL implements MVCC, although each relational database implementation is not the same, but most of the

Log in to MySQL with Root and then run the following code to create the MySQL user and libraryThe account created below: test123 password: 123456 Library name: test123CREATE USER'test123'@'localhost'Identified by'123456'; GRANT USAGE on* . * To'test1

1, Baidu input MySQL2. Go to MySQL website to find the picture place3, in the interface below to find the picture content to download4, install after downloading.The installation process is as follows:1. Unzip the downloaded files and put them under

Problem Description: New database and new table insert data, Chinese garbled problem, even if the character set through the command line or the MySQL client changed to Utf-8 or garbled.Problem reason: This problem is mainly in Linux for centos7

Server-side command SQL In the database system, SQL statements are case-insensitive (uppercase is recommended)? SQL statements can be written in one or more lines, with ";" End? Keywords cannot span multiple lines or shorthand? Use spaces

Common directives instruction function Instructions View/Query Show,select,desc Create Create Delete Drop,delete,truncate Toggle/Enter Use

Overriding an index is exactly the same number of fields that are created for the index and queryUsing Filesort:mysql uses an external index instead of the in-table index order to access the sort operations that MySQL cannot do with the index, which

Review:Linux environment MySQL creates new users and databases and authorizesFirst, the new userLog in to MySQL@>--p@> PasswordCreate userMysql> Insert intoMysql.User(Host,User, Password)Values('localhost','Xdev', Password ('xdev123'));//Refresh

This article mainly introduces MySQL 8.0.112 binary installation, the following steps1. Extracting filesTAR-ZXVF mysql-8.0.11-el7-x86_64.tar.gz2. Move the extracted database filesMV Mysql-8.0.11-el7-x86_64/usr/local/mysql3. Create a MySQL

Springboo Machine integrated MyBatis and MySQL1, adding dependenciesProject Xsi:schemalocation= "http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"xmlns= "http://maven.apache.org/POM/4.0.0" xmlns:xsi= "http://www.w3.org/20

To use Django for project development recently, you need to use the Mysql-python module.In the local installation of the environment when the error occurred,unable to find Vcvarsall.batFind a lot of information on the Internet, found that the window

Although MySQL is rarely used, but the database as a basic skill still can not forget, recently in the study of database isolation level, write a personal understanding to prepare for review.We all know the four characteristics of acid (atomicity,

MySQL like syntaxThe LIKE operator is used in the where expression to search for the specified content in the matching field, with the following syntax:WHERE column like patternWHERE column not as patternWhen you add the not operator to like, it

1.1.Basic Operations Database engine Inodb: Support transactions [atomic operations, complete a number of column operations before the completion of the operation, otherwise rollback] MyISAM: Supports full-text indexing, emphasizing

MySQL time plus and minus functions are Date_add (), Date_sub ()Definition and usageThe Date_add () function adds a specified time interval to a date.The Date_sub () function reduces the specified time interval to a date.GrammarDate_add