• In fact, I once wanted to be a Beipiao


    On the national day, I went to Beijing with my wife for a few days. I went to the city I once yearned for, but I didn’t go to it in the end. Four years ago, when I was just 18 years old, I had a whim on the day when the final exam ended […]

  • The elementui table component merges rows or columns


    introduce 1. Official documents The official document of the method of merging rows or columns is: parameter explain type Optional value Default value span-method Calculation method of merged rows or columns Function({ row, column, rowIndex, columnIndex }) —— —— You can merge rows or columns by passing the span method method to table. The parameter […]

  • Analysis of the underlying operation principle of SQL query


    SQL language everywhere。 SQL is not only the exclusive skill of technical personnel, it seems that everyone can write SQL, just as everyone is a product manager. If you do background development, crud is a routine. If you do data warehouse development, writing SQL may occupy most of your working time. When we understand the […]

  • [invitation] openatom xuberchain developer summer forum starts!


    On the second anniversary of openatom xuperchain open source, we will hold the openatom xuperchain developer summer forum in Pudong New Area of Shanghai on June 25 to invite research institutions, enterprises and other open source ecological partners to discuss the development path and landing direction of blockchain technology. This forum will present a report […]

  • Array of go language foundation


    This paper mainly introduces the go language array and its basic use. Array (array) An array is a collection of elements of the same data type. In go language, an array is determined from the time it is declared, and its members can be modified when it is used, but the size of the array […]

  • Simple instance statement of SQL stored procedure


    1 create database bookshop 2 go 3 4 use bookshop 5 go 6 7 / * personnel list*/ 8 CREATE TABLE employee( 9 emp_no char(5)not null primary key, 10 emp_name char(10) not null, 11 sex char(2) not null, 12 dept char(4) not null, 13 title char(6) not null, 14 date_hired datetime not null, 15 birthday […]

  • Spark learning resources you can’t miss these years


    Link to the original text:Spark learning resources you can’t miss these years Write on the front This series is a combination of my understanding records in the process of learning spark + some understanding of reference articles + some personal experience in the process of practicing spark. Writing such a series is just to sort […]

  • [programming] learning element UI


    Environment construction NPM installation It is recommended to use NPM to install, which can better communicate with userswebpackPackaging tools are used together. npm i element-ui -S CDN At present, it can be passedunpkg.com/element-uiGet the latest version of resources, introduce JS and CSS files on the page to start using. <! — introduce style — > […]

  • Go language series – from array to map


    array An array can hold multiple data of the same type. An array is also a data type. In go, an array is a value type There are six chickens in a chicken farm. Their weight is 3kg, 5kg, 1kg, 3.4kg, 2kg, 50kg. What is the total weight of these six chickens? What is the […]

  • Element checks the table togglerowselection by default


    Although the togglerowselection method is provided on the official website, no demo instance is provided.Through understanding, the special attribute ref of Vue is referenced to DOM element, and then the togglerowselection method on DOM is executed. In the following three different data sources, the corresponding columns are checked by default in table: 1. Write it […]

  • Index usage is not ideal due to order by


    In mysql, indexes are often not used as expected. Today, an order by statement is recorded, which results in indexes not being used as expected. 1. Problem phenomenon 1.1 SQL statement: SELECT DISTINCT p.* FROM tb_name p Where 1 = 1 and p.createdate > = ‘2019-10-23’ and p.createdate < = ‘2019-11-20 24:00:00’ and p.status = […]

  • Android list dialog setitems


    private Button button; Private final charsequence [] items = {“Beijing”, “Shanghai”, “Guangzhou”}; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); button = (Button) findViewById(R.id.button); button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this); Builder.settitle (“please select the following cities”); //Builder. SetMessage (“please select the following […]