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1, Core description of the project 1. Fleck is a relatively simple third-party component to implement websocket, which does not need to install additional containers. There are also several interfaces available. 2. The project is based on. net framework 4.7.2, developed on vs2019, and has not tried to run on the lower version. However, the new ...

Preventing primitives from being deleted by the user can be achieved through ObjectOverrule. The following code: 1. The command AddEraseOverrule creates two primitives and prohibits deletion. 2. Command RemoveEraseOverrule to remove deletion restrictions. static EraseOverrule eraseRule = null; public class EraseO ...

Original address: https://mysqlserverteam.com/mysql-explain-analyze/   MySQL 8.0.18 was just released. October 17, 2019 ), which includes a new feature to analyze and understand how queries are executed: explain analyze. What is explain analyze EXPLAIN ANALYZE is a query analysis tool that tells you how much time MySQL spends on queries and why ...

In the Oracle database, the optimizer needs to rely on the collection of statistical information of related objects in order to generate the optimal execution plan. The database can automatically collect the execution plan or use the package DBMS_STATS is collected manually. This article does not explain the collection of general statistics. It ...

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- ...

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 ...

　　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 ...

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 ...

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 ...

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 ...