Tag:Key value

  • JavaScript has a deep understanding of – set, map, weakset and weakmap

    Time:2021-6-20

    Set The set object allows you to store unique values of any type, whether they are original values or object referencesEssence: constructor, used to generate set data structure describe A set object is a collection of values, and you can iterate its elements in the order in which they are inserted. The elements in the […]

  • Redis series (1): small trial

    Time:2021-6-16

    introduction With the rapid development of the Internet, the traditional relational database (such as mysql, Microsoft SQL server, etc.) can not meet the growing business needs, such as commodity second kill, rush purchase and other very timely functions. With the application of high concurrent access, the system database will collapse. In order to solve this […]

  • Corresponding explanation content of rust programming video tutorial — HashMap

    Time:2021-6-15

    Video address Headline address:https://www.ixigua.com/i676544267458235648…Station B address:https://www.bilibili.com/video/av78062009?…Netease cloud classroom address:https://study.163.com/course/introduction…. Explanation content 1. Hash map(1) The hash map < K, V > type stores a key value K, corresponding to a mapping of value type V. It uses a hash function to map and decide how to put the key and value into memory.(2) All keys […]

  • HTML5 API formdata — using

    Time:2021-6-14

    FormData brief introduction XMLHttpRequest Level 2 adds a new interface, formdata. Using formdata object, we can simulate a series of form controls with some key value pairs through JavaScript. We can also use the send() method of XMLHttpRequest to submit the “form” asynchronously. Compared with ordinary Ajax, the biggest advantage of using formdata is that […]

  • Go operation etcd

    Time:2021-6-13

    Etcd is a popular open source and distributed key value pair data storage system in recent years, which provides shared configuration, service registration and discovery. This paper mainly introduces the installation and use of etcd. etcd Etcd introduction Etcd is an open source and highly available distributed key value storage system developed by go language, […]

  • What is the structure of redis key value pair?

    Time:2021-6-12

    What is the structure of redis key value pair? A global hash table (array) is composed of multiple hash buckets (elements on the array, including entry elements) For example, key name: AAA, key value: BBBThrough hash (AAA), get array subscript 6, then hash bucket 6. The entry element in hash bucket 6 containsKey andValue pointer,Key […]

  • SQL mapping file of mybatis

    Time:2021-6-11

    SQL mapping file General structure of mapping file <?xml version=”1.0″ encoding=”UTF-8″ ?> <!DOCTYPE mapper PUBLIC “-//mybatis.org//DTD Mapper 3.0//EN” “http://mybatis.org/dtd/mybatis-3-mapper.dtd”> <mapper namespace=”com.atguigu.mybatis.dao.EmployeeMapper”> <!– Namespace: name space; The full class name specified as the interface ID: unique identification Resulttype: return value type #{ID}: get the ID value from the passed parameter public Employee getEmpById(Integer id); –> <select […]

  • Re learning react — higher order components

    Time:2021-6-4

    1、 Advanced component Foundation In a word: it is a function that passes in a component and returns a new component; The function is to enhance the incoming components const lessons = [ {stage: ‘react’, Title: ‘componentization 1’}, {stage: ‘react’, Title: ‘componentization 2’}, {stage: ‘react’, Title: ‘componentization 3’} ]; //Function component function Lesson(props: any) { […]

  • (5) Django web development cookie and session

    Time:2021-6-3

    1、 Cookie 1.1 what is a cookie? A cookie is a small piece of text information generated by the server and stored in the browser.Characteristics of Cookie:1) WithKey value pairIt can be stored in different ways.2) When you visit a website through a browser, all cookie information related to the website stored in the browser […]

  • Map of go language foundation

    Time:2021-5-12

    The mapping container provided in go language ismapFor internal useHash table (hash)realization. Map is an unordered map based onkey-valueMap in go language is a reference type, which must be initialized before it can be used. Map definition In go languagemapThe definition syntax of is as follows: map[KeyType]ValueType Among them, Keytype: indicates the type of the […]

  • NoSQL 1: memcached

    Time:2021-5-10

    1、 Introduction to NoSQL NoSQL is not no SQL, but not only SQL. NoSQL is not used to replace relational database, but in some scenarios where relational database is not suitable, NoSQL database can be used for optimization, while relational database is still used for main and conventional data in the system.The commonly used NoSQL […]

  • Map for easy understanding of data structure

    Time:2021-5-4

    preface Original intention:I’ve been reading recentlyDeep understanding of ES6This book, I haven’t learned ES6 grammar thoroughly before, so I’ll read it again when I’m not busy. I’ll share my notes with you. Don’t spray if you don’t like it. Suitable for people:The primary development of the front-end, big man detour. Content structure:Understanding Map > basic […]