MongoDB basic knowledge and operation literacy!

MongoDB learning notes - updating json can describe a variety of relationships for us: one to one, one to many, many to one, and many to many Similar to js syntax Creating a record will automatically generate an "id" primary key, unique id, which represents the Object, and can also be declared as user-defined data {_id:"123"} BSON and ...

Posted on Fri, 15 Nov 2019 00:12:11 -0500 by toplay

Getting started with PostgreSQL - installation and basic use (Ubuntu 16)

Getting started with PostgreSQL - installation and basic use (Ubuntu) PostgreSQL is a free object relational database server (ORDBMS), known as "the most advanced open source relational database in the world". PostgreSQL is an object relational database based on Postgres version 4.2 developed by the computer department of the Univers ...

Posted on Thu, 14 Nov 2019 23:13:34 -0500 by bad_goose

02Spring IOC configuration based on xml -- three ways to instantiate Bean

maven dependence <dependencies> <!--IOC Dependent dependence--> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>5.0.6.RELEASE</version> </dependency> <depend ...

Posted on Thu, 14 Nov 2019 22:52:11 -0500 by DaPrince

Analysis of the principle of the Robust thermal restoration framework of meituan

I. current situation of thermal repair frame At present, the hot fix framework mainly includes QQ space patch, HotFix, Tinker, robot, etc. According to the principle, the thermal repair framework can be roughly divided into three categories: Intervening ClassLoader to load dex based on multidex mechanism native substitution method structure In ...

Posted on Thu, 14 Nov 2019 22:49:36 -0500 by Timewell

Hystrix Thread Pool Configuration

This paper introduces the working principle and parameter configuration of Hystrix thread pool, points out the existing problems and provides a solution to avoid them. It is necessary to have a good understanding of Hystrix in reading this article. Text discussion based on hystrix 1.5.18: <dependency> <groupId>com.netfl ...

Posted on Thu, 14 Nov 2019 21:49:37 -0500 by nivosh

Introduction to python built-in module collections

Catalog Introduction to python built-in module collections 1,namedtuple 2,deque 3,defaultdict 4,OrderedDict 5,ChainMap 6,Counter 7. Summary Introduction to python built-in module collections collections is a collection module built into Python that provides ...

Posted on Thu, 14 Nov 2019 21:45:44 -0500 by ub_kh

Do you really know dichotomy?

Binary Search Algorithm Resolution Basic framework: int binarySearch(int[] nums, int target) { int left = 0, right = ...; while(...) { int mid = (right + left) / 2; if (nums[mid] == target) { ... } else if (nums[mid] < target) { left = ... } else if (nums[mid] > target) { ...

Posted on Thu, 14 Nov 2019 21:21:59 -0500 by artfuldrone

JavaScript code performance optimization - from sorting to processing

Recently, we did performance optimization for our console, this time recording performance checks and optimizations for code execution (DOM operations are not included on pure JS).Other optimizations will be shared later. Console address: https://console.ucloud.cn/ Performance problem investigation and collection First, you need to sort out the ...

Posted on Thu, 14 Nov 2019 21:20:30 -0500 by biannucci

[Front-end beginners can also do big projects]: Build your own online Visio project from scratch [ReactJS + UmiJS + DvaJS]

This series of tutorials teaches you how to use the Open Source js Drawing Library To create your own online drawing software.You can also look at the development tutorial for this drawing library.If you feel good, please give us a compliment and let us be more motivated to do it! This series of tutorials focuses on how to develop your own draw ...

Posted on Thu, 14 Nov 2019 21:10:01 -0500 by kpetsche20

Basic concepts of Java threading

Java Thread Interrupt In Java, there is no way to force thread termination.However, the interrupt method can be used to request thread termination.When the interrupt method is called on a thread, the interrupt state of the thread is set. public void interrupt() { if (this != Thread.currentThread()) checkAccess(); ...

Posted on Thu, 14 Nov 2019 20:56:51 -0500 by sara123