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brief introduction As the name suggests, object pool is the pool where objects are stored. Like thread pool, database connection pool and http connection pool, it is a typical pool design idea. The advantage of object pool is that it can centrally manage the objects in the pool and reduce the frequent creation and destruction of long-term obj ...

1, Data We talked about the log before the database drop. Today, it's very troublesome to analyze the data drop. But the principle is the same. In the previous analysis, we can clearly know that in MySql, no matter what kind of data, it enters the cache first, and then drops the disk to save. In the database, what is the most important? Of cou ...

scene Winform establishes a connection with Mysql8 and obtains all tables, then checks the specified table, regularly backs up the database and exports it as an sql file. And you can set the number of overwriting backups. For example, if it is set to 7, the sql file backed up for the first time will be replaced when backing up to the eighth ti ...

1, Foreword For any framework, a series of initialization is required before use, and MyBatis is no exception. 2, What did the initialization of MyBatis do 2.1 the initialization process of mybatis is the process of loading the configuration information required by its own runtime The initialization of any framework is nothing more than ...

Original website: JPA--SpringBoot -- custom SQL -- Integration / method / how / how / instance / example / actual combat / tutorial -- spring data JPA_ CSDN blog brief introduction explain         When JPA customizes SQL, all additions, deletions and queries are annotated with @ Query, except that the statements inside a ...

In a recent project, I used. net core 2.1, and then Redis for caching. The cache related package was written by colleagues, and the driver used was StackExchange.Redis version 2.0.571. I've always heard that there was a TimeOut bug when the driver was concurrent. After the project was almost developed, I tested it and simply simulated 30 users' ...

0. Test data set and description 0.1 preparation of test data [test data 1] WITH Temp1 AS ( SELECT 'Zhang San' AS Name, 'chinese' AS Subject, one hundred AS Scores UNION ALL SELECT 'Zhang San' AS Name, 'mathematics' AS Subject, ninety AS Scores UNION ALL SELECT 'Zhang San' AS Name, 'English' AS Subject, eighty AS Scores UNION ALL SELECT 'Li ...

Introduction to using components with known vulnerabilities Causes of loopholes There are known security vulnerabilities in the frameworks, libraries and toolkits used in the application technology stack. Attack mode Exploit known vulnerabilities in frameworks, libraries, tools, etc. in the application technology stack to obtain high permis ...

###Title Practice sql Download: 1. Query the number of students selected for each course; 2. Find out the student numbers and names of all students who have taken only one course; 3. Query the number of boys and girls; 4. Check the list of students surnamed "Zhang"; 5. Query the list of students with the same name and surname, and cou ...

query 1. Data preparation 1.1 create table // Create department table create table if not exists dept ( deptno int, dname string, loc int ) row format delimited fields terminated by '\t'; // Create employee table create table if not exists emp ( empno int, ename string, job string, mgr int, hiredate string, ...