Tag:primary

  • Solution to multiple primary key defined error in MySQL

    Time:2021-2-7

    There are two ways to create a primary key: Create table name( Field name type, Field name type, …… primary key(name) ); Or is it Create table name( Field name type primary key, Field name type, …… ); But note that if you want to create a composite primary key, you can’t use the second […]

  • React Redux advanced Immutable.js

    Time:2020-6-25

    Immutable.js Advantages of immutable 1. Guarantee immutability (each pass Immutable.js The object of operation will return a new object) 2. Rich API 3. Good performance (sharing data structure through dictionary tree) <br/>Immutable problems 1. The interaction with native JS is not friendly (objects generated through immutable are different from native JS in operation, such as […]

  • Asp.Net Webapi upload file method (native JS upload and JQ Ajax upload)

    Time:2020-6-19

    Asp.Net Webapi upload file method Implementation function: 1. Native JS calls API upload 2. JQ Ajax calls API upload back-end Model /// ///Upload files (if you encounter any unclear or find bug, please join QQ group: Java. Net go PHP UI group: 574879752 direct @ group master) /// public class FileResp { /// ///File path […]

  • React native: a revolution in app

    Time:2020-6-17

    Remember from 2010, the front-end is gradually shining. Before that, I was a diligent back-end engineer. My daily job was to write some front-end code like table while working on the back-end code. Well, it’s not the front end, it’s just a nesting of tables. At that time, the front end was really rubbish. That […]

  • Hybrid app development practice (3): nvue in uni app

    Time:2020-6-15

    ​Official accountCabbage in frontMore front-end dry goods are waiting for you! The official account will share the front-end technology from time to time, making progress every day and growing with everyone. A native rendering engine based on weex is built in the uni app app to provide native rendering capabilities. ​ To use the native […]

  • The principle of interaction between H5 and native app

    Time:2020-6-9

    The principle of interaction between H5 and native app Nowadays, mobile web applications need to interact and communicate with native apps (running inwebviewFor example, wechatjssdk, viawindow.wxObject to call some functions of the native app. So, this time, let’s explore the interaction principle between H5 and native app. The interaction between H5 and native app is […]

  • An article to understand many solutions for H5 to open app

    Time:2020-6-5

    In fact, it should be a very simple thing to open the app in H5. It’s just to call a protocol or interface on the H5 page to open the app. However, due to the development of technical solutions and the blocking of some traffic apps, the solution to evoke app becomes more complicated. This […]

  • Database layer of SAP NetWeaver and hybris

    Time:2020-6-4

    ABAP Netweaver In SAP’s ABAP application based on NetWeaver, application developers use open SQL to access the database. These open SQL will be converted by database interface into native SQL statements supported by various database providers and then executed. The database providers supported by NetWeaver can see in the DBMS field of table dbcon: In […]

  • Simple use of a beautiful toast third-party library

    Time:2020-6-4

    I used to use the Android native toast. I feel that there is no need to work hard on it. When I saw the toast, it was immediately circled. It’s really beautiful. Project address As we all know, the usage of Android native toast is Toast.makeText ( MainActivity.this , “toast display content”, Toast.LENGTH_ SHORT).show(); Method […]

  • angular4 @ViewChild ElementRef renderer

    Time:2020-5-29

    angular4 @ViewChild ElementRef renderer2 How does angular operate DOM? This is a problem. If you are proficient in jQuery, you will want to introduce jQuery to operate, but this is not a good way Let’s see if elementref and render2 meet your needs: Select nodes in component <! — View — > <div #mydiv><input></div> //Select. […]

  • Common development mode of app

    Time:2020-5-27

    Common development mode of app Native App The traditional native app development mode has two major systems, IOS and Android, which need to develop their own apps in their own languages. Advantages: performance and experience are the best.Disadvantages: high cost of development and release, trouble to maintain multiple versions of updates and upgrades, and high […]

  • JSON data sending and receiving

    Time:2020-5-20

    Native xmlhttp send function login() { var username =document.getElementById(“username”).value; var password = document.getElementById(“password”).value; var remember =document.getElementById(“remember”).checked; var xmlhttp; if (window.XMLHttpRequest) { //IE7 +, Firefox, chrome, opera, Safari browser execution code xmlhttp=new XMLHttpRequest(); } else { //IE6, IE5 browser execution code xmlhttp=new ActiveXObject(“Microsoft.XMLHTTP”); } xmlhttp.onreadystatechange=function() { if (xmlhttp.readyState===4 && xmlhttp.status===200) { … } }; xmlhttp.open(“POST”,”/flask/login”,true); xmlhttp.setRequestHeader(“Content-type”,”application/json”); […]