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MongoDB learning notes 01 - start MongoDB // Open service sudo service mongodb start // Start MongoDB mongo 02 - database operation command // View the database in use in the current period db // View all databases show dbs // Connect or create myTest database use myTest // Destroy myTest database use myTest db.dropDatabase() 03 - creati ...

preface Before reading this article, you need to understand the relevant contents of OAuth 2.0 licensing agreement. You can refer to my Last article   OAuth 2.0 adventure [1]. The full name of PKCE is Proof Key for Code Exchange, which was released in 2015. It is an extended protocol of OAuth 2.0 core, so it can be used in combin ...

Zero, write in front First of all, it is purely entertainment, and there are many loose places!!           Mankiw's macroeconomics mentioned an example when talking about the CPI (consumer price index), that is, avatar ranked first at the box office with us $761 million at that time, but after considering inflation, a ...

tar command Use the tar command to package, compress, and decompress files: Compress the file using gzip and specify the compression name tar_gzip.tar.gz [root@ikta ~]# tar -czvf tar_gzip.tar.gz find_test1 find_test2 find_test1 find_test2 Compress the folder using bzip2 and specify the compression name tar_bzip2.tar.bz2 [root@ikta ~]# tar ...

Experiment Task Two #Program Source 1 #include <iostream> 2 #include <typeinfo> 3 4 // definitation of Graph 5 class Graph 6 { 7 public: 8 virtual void draw() { std::cout << "Graph::draw() : just as an interface\n"; } 9 }; 10 11 12 // definition of Rectangle, derived from Graph 13 class Rectangle : public Grap ...

Quick sort basic thought Quicksort is an improvement on bubble sort. The basic idea is: through one-time sorting, the data to be sorted is divided into two independent parts. All the data in one part is smaller than all the data in the other part, and then the two parts of data are sorted quickly according to this method. The whole sorting pro ...

Singleton mode Singleton Pattern is a creation pattern. It involves a single class that is responsible for creating its own objects and ensuring that only one object is created. This class provides a unique way to access objects, which can be accessed directly without instantiating the objects of this class. Attention A singleton class can c ...

1 object oriented overview 1.1 process oriented and object-oriented Process oriented: process oriented is to analyze the steps needed to solve the problem, then implement these steps one by one with functions, and call them in turn when using. The core of process oriented is the process of solving problems. Object oriented: object orient ...

1, IOC container IOC underlying principle Concept and principle of IOC 1. What is IOC? (1) Control inversion, and leave the object creation and calling process between objects to Spring for management (2) Purpose of using IOC: to reduce coupling 2.IOC underlying principle (1) xml parsing, factory schema, reflection IOC operation The ...

Design Patterns -- the basis of Reusable Object-Oriented Software Design pattern is a set of code design experience that is repeatedly used, known by most people, classified and catalogued. The purpose of using design patterns is to reuse the code, make the code easier to be understood by others and ensure the reliability of the code. There is ...