Programmer Group

front word : \textcolor{green} {Preface:} preface: 💞 In the previous article, we learned what Mybatis is and also wrote our first Mybatis program. Next, let's take a look ...

preface Our last article introduced the Servlet request and response interface. In this article, I will introduce the simulation of the educational administration system based on the current knowledge. Its functions include user registration, user logout, user information modification and user query. It will use the knowledge of JDBC, DA ...

preface Recently, a customer of the company used PostgreSql to store data. In the export function, it was found that in the case of big data, the memory will grow until it overflows. Because the fetchSize is set for stream query in the export function, there will be no memory overflow. Then the investigation found that all the data were obtain ...

ETCD introduction ETCD   It is a distributed and consistent KV storage system for shared configuration and service discovery. Etcd is an open source project initiated by CoreOS, and the license agreement is Apache. ETCD usage scenario ETCD has many usage scenarios, including but not limited to: configuration managementService registere ...

Business scenarioMulti tenancy of ClickHouse is a very necessary scenario. If there are no restrictions, users may consume too much resources of database services and affect the use of other users. This paper attempts to show you another relatively cheap method besides hardware level isolation.This article first describes the resource restricti ...

(31) create a view of information department student information create view IS_Student as select * from student where sdept = 'IS'; (32) query students younger than 20 years old in the student view of the information department select * from IS_Student where Sage < 20; (33) delete all course selection records of Ma Chaoyang delete f ...

Database programming (JDBC) 1. Database programming: JDBC JDBC, namely Java Database Connectivity. Is a Java API for executing SQL statements. It is a database connection specification in Java. This API is composed of some classes and interfaces in java.sql. Javax.sql. Package. It provides a standard API for Java developers to operate ...

Basic introduction and configuration Video link #Crazy God said sql Query data storage place Start service + enter database management system 1 – start local mysql service computer management system command line net stop/start mysqllin 2 – enter the management system with the password Username root password 12345 ...

In the face of more and more high concurrency scenarios, the display of current limit is particularly important. Of course, there are many ways to implement current limiting. Redis has very powerful functions. I have practiced three ways with redis, which can be implemented in a relatively simple way. Redis can not only limit current, but also ...

The theme of this time is to store data in CSV (or other) file format into MySQL database, and the table structure primary key should be established. Including the processing of date format. Although it's very simple, there are many details and a wide range of knowledge, so write it down. Three tables, as follows articles: issues: sales: i ...