• Mysql database import SQL error (unknown collation: ‘utf8mb4_ 0900_ ai_ ci’ )


    Error reason: high version database (8.0) transfers SQL file and imports low version database (5.7) terms of settlement: Scheme 1: upgrade Mysql to a higher version Scheme 2: the SQL file to be imported, the utf8mb4_0900_ai_ciReplace all withutf8_general_ci utf8mb4Replace withutf8 Re execute SQL file

  • Check in function, MySQL or redis?


    Now in the development of website and app, sign in is a very common function, such as microblog sign in, send points, sign in leaderboard.       Such as mobile app, check-in and delivery of traffic.     User check-in is an effective means to improve user stickiness, good use can get twice the […]

  • SQL one stop solution for heterogeneous data of deep dry goods


    At the recent GDG developer conference in Guangzhou, Dong Lin, senior technical director of getpush, took “SQL one-stop solution for heterogeneous data” as the theme, and deeply shared many years of practical experience of getpush in the field of SQL. This article will elaborate the unified SQL from three aspects 1、 Why unify SQL 2、 […]

  • How to understand middleware middleware of Redux


    How to understand middleware middleware of Redux If we need to print out the action and the state after the action before and after the dispatch, what do we need to doThe implementation scheme is as follows:First of all, we want to add a console before and after each call Add console before and after […]

  • Interview question: JS get the number of days in a month


    Gets the number of days in a monthThis problem is usually under studyswitch(){}One chapter is a case study. Our solution is based on a doggerel:Thirty one days is never bad, forty-six ninety-one days is 30 days a month, but twenty-eight days in February. In leap year, one day is added。(I searched it. I forgot how […]

  • React – how to use the modal component of antd more elegantly


    preface First, let’s take a lookAnt DesignThe first one on the official website is aboutModalOfdemo import { Modal, Button } from ‘antd’; class App extends React.Component { state = { visible: false }; showModal = () => { this.setState({ visible: true, }); }; handleOk = e => { console.log(e); this.setState({ visible: false, }); }; handleCancel […]

  • The problem of file upload progress display in react native


    The daily article series is used to record the problems encountered in daily work and life and possible (unsolved) solutions, not limited to technology. problem One of the problems encountered and solved today is how to display the upload progress bar when uploading files in react native describe There are many solutions for uploading files […]

  • Installation and configuration of Java environment in CentOS


    1、 Download 1.1 scheme 1 open the URL and select JDK1.8 to download http://www.oracle.com/technet… I choose Linux x64 version: Through the browser console, open all and see the requested URL Copy URL: https://download.oracle.com/otn/java/jdk/8u261-b12/a4634525489241b9a9e1aa73d9e118e6/jdk-8u261-linux-x64.tar.gz?AuthParam=1600091044_31c1eb94fbbe8bda12225c3e79714b87 Download with WGet in CentOS wget https://download.oracle.com/otn/java/jdk/8u261-b12/a4634525489241b9a9e1aa73d9e118e6/jdk-8u261-linux-x64.tar.gz?AuthParam=1600091044_31c1eb94fbbe8bda12225c3e79714b87 Discovery tips 403 There should be no authority wget https://download.oracle.com/otn/java/jdk/8u261-b12/5b13a193868b4bf28bcb45c792fce896/jdk-8u261-linux-x64.tar.gz?AuthParam=1600091044_31c1eb94fbbe8bda12225c3e79714b87 It can be solved by […]

  • Alignment of compatible text in different browsers


    In the front-end layout of the form, we often need to align the two ends of the prompt text in the text box The rough way is to add labels to the text that needs to be isolated margins, and then control the margins of each text separately. This method is more accurate than adding […]

  • How to understand multi tenant architecture? (transfer)


    Transferred from: https://www.cnblogs.com/pingfan21/p/7478242.html Some time ago, the company’s products evolved from architecture to multi tenant architecture. When I first heard about multi tenancy, I was quite puzzled and didn’t understand. But when I gradually look through the materials and develop the functions. Continuously deepen the understanding of multi tenant. Although I only know a little […]

  • Android solves the problem that Chinese characters cannot be vertically centered under VW / VH layout


    resolvent explainAt present, no perfect solution has been found.Operation steps① Set HTML tag: < HTML lang = “zh CMN Hans” >② Set password box CSS Style: font family: monospace;explainFor point 1, please refer to the first answer in reference 1 below;As for point 2, setting “< HTML lang =” zh CMN Hans “>” on the […]

  • Easily manage multiple gopaths


    Original linkOriginal author: Herbert FischerTranslator: xcshuan Usually, there is only one gopath in my machine, which is also recommended by most gophers. However, sometimes we need to work with different versions of different projects with the same dependencies and update them accurately. We just don’t want to destroy or mess up what we’re working on. […]