0. Chapter 0 of MySql, installation and cluster configuration

Chapter 0 of MySql, installation and cluster configuration 1, MySql installation 1. RPM installation RPM installation, unable to customize some installation paths and configuration file paths ##Fill in the pit later 2. Generic installation Binary precompiled Generic, download address: https://cdn.mysql.com/archives/mysql-5.7/mysql- ...

Added by khendar on Tue, 26 May 2020 17:54:42 +0300

C ා data operation series - 16 SqlSugar conclusion

0. Preface In the previous article, we introduced the addition, deletion, modification and query of SqlSugar in detail, which has satisfied our use in daily engineering development. However, there are a few methods that are not commonly used in development, but are very useful. Let's see what else is interesting. 1. Unusual query Previously, we ...

Added by paullb on Tue, 26 May 2020 11:22:24 +0300

ORM component ELinq - Fluent API for mapping configuration

  Part I This paper introduces the ELinq mapping configuration mode based on Attribute. This paper will introduce the mapping configuration mode based on fluent API. This article still takes the customers table and Orders table of Northwind database as an example. Customers and Orders are one to many relationships. 1. Entity classes of cust ...

Added by Karve on Sun, 24 May 2020 19:10:17 +0300

One key package / deployment scheme of Ctrip Apollo

Apollo-docker One click package / deployment scheme of Ctrip Apollo. Almost no need to modify any Apollo source code or configuration to build a rapid development / test environment. Project address: https://gitee.com/ellipse/apollo-docker 1. Download source code Apollo git clone https://gitee.com/nobodyiam/apollo.git Compile script git clone ...

Added by S A N T A on Sun, 24 May 2020 17:56:59 +0300

How to deal with the problem that the cloud server cannot access the database remotely after it is installed

Today, my colleague said that a new cloud server is installed, and it is normal to log in Using ssh, but the above service port of Dayun database cannot be accessed. Using netstat ANP to view the port is normal to listen, and the listening address is also allowed to be accessed by any ip And the firewall and iptables are both closed I was also ...

Added by Maskeeper on Sun, 24 May 2020 15:00:06 +0300

Optimistic Lock (CAS) retry data version not updated under mysql transaction default isolation level

Exception Information Ccom.mysql.cj.jdbc.exceptions.MySQLTransactionRollbackException: Lock wait timeout exceeded; try restarting transaction Reasons for the problem When optimistic locks modify data, the data version number has been modified, causing the modification to fail. When retrying the modification, each time the data read from the d ...

Added by xsist10 on Fri, 22 May 2020 21:51:58 +0300

oracle uses stored procedures for row to column conversion (executing dynamic SQL statements)

---------------------------------------------------------------Table building----------------Determine whether the student table exists declare num number; --Declare parameters num type number begin --start select count(1) into num from user_tables where table_name='student'; if num>0 then execute immediate 'drop table st ...

Added by crinkle on Thu, 21 May 2020 18:21:15 +0300

Python easy map visualization (with detailed source code)

preface The text and pictures of this article are from the Internet, only for learning and communication, not for any commercial purpose. The copyright belongs to the original author. If you have any questions, please contact us in time for handling. Python has a lot of map visualization libraries. Although Matplotlib library is very power ...

Added by dannyluked on Thu, 21 May 2020 09:54:45 +0300

eggjs Learning Notes Day 35: Simple Logic for Background Login Authentication

1. After getting the user name, password and authentication code in the background: (1) Get the data submitted by the form (2) Determine whether the verification code is correct or not If the verification code is correct: 1. Encrypt the password in the form by MD5 MD5 moduleHttps://www.npmjs.com/package/md5 1,install cnpm install md5 --sav ...

Added by jjoves on Wed, 20 May 2020 20:28:13 +0300

Basic usage of JDBC

JDBC fixing steps: Load driver String url="jdbc:mysql://localhost:3306/jdbcstudy?useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT"; String username="root"; String password="123456"; Class.forName("com.mysql.cj.jdbc.Driver");//I don't know why com.mysql.jdbc.Driver will report an error. Please leave a message if you have any ...

Added by PHPfolife on Wed, 20 May 2020 17:31:54 +0300