Programmer Think

The JOIN can be roughly divided into the following three categories according to its functions: A INNER JOIN B on condition (inner join, or equivalent join): gets the record of the matching relationship between the fields in two tables. A LEFT JOIN B on condition (left join): gets all records in the left table, even if the right table does n ...

1. First install the jave environment jdk Download address I use the latest version. Sometimes the version corresponds to elastic search 2. Install elastic search Download address 3. Install the Laravel scout full-text search package. Here I use version 5.0.3, Tamayo / Laravel scout elastic. The version here is very important, otherwise I will ...

node, express and koa connect MongoDB in the same way. We use mongoose module to connect Read this article about connecting to mysql: koa,express,node general method to connect MySQL Here is just a brief list of the structure of connecting MongoDB. In fact, to really understand MongoDB, you need a lot of knowledge points, such as MongoDB data t ...

1. Install yum repo There is no mysql in the yum source of centos (you can try to use the installation command directly: Yum install mysql server). You need to download the yum repo configuration file on mysql's official website, and then install: #download wget https://dev.mysql.com/get/mysql57-community-release-el7-9.noarch.rpm #repo inst ...

brief introduction JSON Web Token (JWT) is the most popular cross domain authentication solution. Introduction to JSON Web Token - Ruan Yifeng , this article can help you understand the concept of jwt. This paper focuses on Spring Boot combined with jwt to realize the safe calling of interface in front and back end separation. Quick start The p ...

By using FlaskForm, the form processing can be realized conveniently and quickly. Explain Operating system: Windows 10 Python version: 3.7x Virtual Environment Manager: virtualenv Code editor: VS Code Experimental target Through the use of flask? WTF form related operations, and complete the new user registration. install pip install flask ...

Affairs: Why do you want to open a transaction? In the program, it's not just compiled, but the same as the logical line. Transactions can help us to execute logic better Data source: Database connection optimization helps us link databases faster If the data source has a database pool, you can take it directly from the database pool import co ...

Distributed applications have a variety of problems.To solve these problems, besides applying some monitoring buried points by yourself, there should be some peripheral systems for active detection and discovery. That's what APM tools do. SkyWalking is an excellent APM application from open source and has become a top-level project for apache. ...

Written in front Mysql is a magical relational database. I really feel that it's awesome. Because the projects I've done are quite miscellaneous, I've met Oracle database before, which gives me the impression that Oracle is very cumbersome and cumbersome, with many configurations. If it's used for small projects, it's like killing chickens and ...

On the basis of creating django project, explain the use of orm framework Note: first, create a database manually or by command in mysql, and I will create a database named orm. 1: configure mysql database link string and time zone configuration in settings.py file in project folder # Registered app INSTALLED_APPS = [ 'teacher', ...