MySQL

Let's start with the backstage.1. Design of the tablePARENT_ID is the ID of another record, and the infinite pole table design can refer to http://m.blog.csdn.net/Rookie_Or_Veteran/article/details/757113862.mysql query is easy, the key is to find

MySQL uses these two fields, almost all of them are necessary.Used to be automatically established, and now hand-built, it is necessary to find information to fix it.Reference

Note: Part of the content refers to HTTP://BLOG.SINA.COM.CN/S/BLOG_4AC9F56E0101G881.HTML1, MongoDB data to MYSQL1) in kettle, MongoDB input component.2) Edit component input Connection informationSelect DatabaseWrite query statementsSelect a field.

1. Export the entire databaseMysqldump-u user name-p database name > exported file nameMysqldump-u dbuser-p dbname > Dbname.sql2. Export a tableMysqldump-u user name-P database name Table name > exported file nameMysqldump-u dbuser-p dbname users>

Recent business Feedback A query exception problem requires the DBA to interpret the query result exceptions and help them resolve the problem. The problem essence is the problem of sorting the maximum within a group, and I built the test case

First, InnoDB change buffer introduction:1. InnoDB change buffer is an optimization of disk IO for OLTP scenarios (I also feel that this is not very like a word, but it is very accurate to explainInnoDB Change buffer function)Second, InnoDB change

Extension examplesInsert a recordINSERT into table name [(Field 1,..., field N)] VALUES (value 1,..., value N)Insert the results of a queryINSERT into table name (Field 1,..., field N) VALUES subqueryExample: INSERT into Scores VALUES ("990301",

For InnoDB, the primary key is the clustered index, and if there is no primary key definition, the first unique non-null index is used as the clustered index.If there is no primary key and no appropriate unique index, then InnoDB generates a hidden

First, configure the environment:Os:win10mysql:5.7.19Second, my MySQL configuration file (My.ini) is as follows:[Client]port=3306default-character-set=utf8[mysqld] #Path to install software directory Basedir=e:\mysql-5.7.19#path To the database

The Elasticsearch of the company's Project Search section, then the data synchronization between the two is a problem.Online to find a few bags, but all have their own shortcomings, the final decision or write a script, the general idea is as

Enter the database　　Use library name;CREATE TABLE structureSyntax: CREATE table library name. Table Name (Field name data type constraint,Field name data type constraint）Create Table text . T_user ( int), varchar(tenView all TablesShow

When you use the Select ... with load DATA infile. into outfile the fields and processing options for the two commands must match when the data in a database is written into a file and then immediately read back to the database, otherwise, LOAD data

Constraints on SQLA constraint is a restriction that ensures the integrity and uniqueness of a table's data by restricting the data on the table's rows or columns. 、1 Constraint classificationA constraint is a restriction that ensures the integrity

MySQL database when you bulk update a table's fields, the syntax is as follows:UPDATE A as aINNER JOIN (SELECT*FromAWHERE....) as B on a.order_id = b.order_idSET a.pay_status = 2, a.abnormal = 4;Example :UPDATE Yamibuy_master.xysc_order_info as

MySQL is a free, open-source relational database.Although MySQL was acquired by Oracle Corporation. But Oracle does not limit the development of MySQL.MySQL is currently the most widely used relational database, and many large companies are using it.

MySQL installation: 1, download mysql repo source wget http://repo.mysql.com/mysql-community-release-el7-5.noarch.rpm2, Installing the MYSQL-COMMUNITY-RELEASE-EL7-5.NOARCH.RPM package  rpm -ivh mysql-community-release-el7-5.noarch.rpm   NOTE: After

Migration of tables between databases on the same server:CREATE TABLE Db.tablename as SELECT * from Db2.tablename;This SQL is used by MySQL to copy a table from a DB2 database on one server to another database db, and to copy the structure of the

The MySQL binary log, known as Binlog, records the operation of database modification data and can be used as a data recovery.There are three ways to record Binlog1, statementThe original Sql,io amount for the record modification data is small. When

MySQL Study Notes 13 group replication concepts, mysql Study Notes 13 groups The main content of this article is as follows:1. Background of group Replication2. Comparison of several Replication technologies3. Failure Detection4. Group members5.

MySql successfully inserted data but reported [Err] 1055, err1055 1. Problem: In the past two days, the insert operation is performed. mysql version is 5.7. After the insert operation is successful, an error of [Err] 1055 is reported. The details