• Problems encountered in upgrading xcode12


    Error one Reactnative report ‘event2 / event config. H’ file not found solution open testApp.xcworkspace ‘event2 / event config. H’ file not found It’s flipper – Due to folly version, modify the podfile file under IOS file as follows use_ Flip! To use_ flipper!({ ‘Flipper-Folly’ => ‘2.3.0’ }) Save it after modification, and save it […]

  • SQLITE_ERROR – table XX has no column named currency


    During the sap cloud application programming exercise, we encountered the following error message:SQLITE_ERROR: table sap_capire_bookshop_books has no column named currency In my schema definition, there is a field called current in books entity, but its data type is currency, which comes from @ SAP / CdS / common, not build in data type, such as […]

  • Vue + websocket for real-time page refresh and long connection


    Implementation of long link between Vue and websocket export default { data() { return { websock: null, } }, created(){ //Open long connection when the page first enters this.initWebSocket() }, destroyed: function() {  //Close long connection on page destruction       this.websocketclose();     },     methods: {       Initwebsocket() {// initialize weasocket         Const wsuri = + “/ websocket / […]

  • Basic understanding of express framework


    introduction *Because nodejs was learned a long time ago, and now we have forgotten the grammar rules. Now we start from the framework and understand nodejs in the opposite way.It’s very troublesome to create a web server in nodejs. To use the HTTP module, the express framework is a tool to optimize such a process.When […]

  • “Failed to start MySQL server”


    No matter how many times you have installed mysql, there are still all kinds of errors. Now that they appear, try to solve them: OK! Next, I will teach you how to check the error log to solve the code errors. Error:   After some column restart operations and checking the error details, we can’t […]

  • “@ionic-native/native-storage” has missing dependencies


    When ionic refers to the native plug-in, it will prompt this error. Generally, the underlined package is not introducedJust execute the following command:npm install @ionic-native/core –save

  • Cell error: databasewrapper objects created in a thread can only


    Cell error: databasewrapper objects created in a thread can only be used in that same threadFor reference:https://www.distributedpython… Change the start command of cell to: celery -A yourapp.celery worker –loglevel=info –pool=solo

  • First knowledge of distributed: MIT 6.284 series (1)


    preface This series is derived from”Manong turns over”The reading activities initiated by the knowledge planet are organized by the [email protected] UDP doesn’t lose packetsWe abandoned the traditional books and began to introduce the top graduate course < 6.824 >, which is the inventor of worm virus many years agoRobert MorrisThe big man teaches, belongs toMITThe […]

  • Rabbitmq installation (system error 5 occurred). Access denied. System error 1067 occurred. Process terminated unexpectedly.)


    Rabbitmq installation steps (Windows) 1. Rabbitmq is built on the powerful Erlang OTP platform, so we need to install it firstErlang。 2. Next, install the rabbitmq servicerabbitmq-server。 3. Start rabbitmq: (1) Right click to open the CMD window in the way of administrator (if it is not opened in the way of administrator, an error […]

  • Modify pointer with C + + const


    Wild pointer is a pointer to illegal memory. There are three ways to modify a pointer with const const pointer Features: the point of the pointer can be modified; the value of the pointer cannot be modified. int a = 10,b = 10; const int* p = &a; *P = 20; // error P = […]

  • Talk about the pitfalls of small program cloud development


    Talk about the pitfalls of small program cloud development When writing code, it is inevitable to make some low-end mistakes. Here are some mistakes I have made, hoping to help other scholars. Error examples // index.js const cloud = require(‘wx-server-sdk’) //It is here that the author makes a very simple mistake. I write “request promise” […]

  • Redis basic business


    If redis needs to execute a set of commands, in order to maintain the consistency and continuity of data, it needs to use transaction. In this paper, some simple examples are given to briefly describe the content related to redis transaction, which is only for learning and sharing. If there are any shortcomings, please correct […]