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Use the $push operator to add a sub-document. Let us first create a collection with documents −> db.subDocumentToSubDocumentDemo.insertOne( { "_id" :101, "StudentName" : "Larry", "StudentAge" : 21, "StudentDetails" : [ { "StudentCountryName" : "US", "StudentFavouriteSubjectList" : [ ] } ] } ); { "acknowledged" : true, "insertedId" : 101 }Following is the query to display all documents from a collection with the help ... Read More
A Json array is an ordered collection of values that are enclosed in square brackets i.e. it begins with ‘[’ and ends with ‘]’. The values in the arrays are separated by ‘, ’ (comma).Sample JSON array{ "books": [ Java, JavaFX, Hbase, Cassandra, WebGL, JOGL] }The json-simple is a light weight library which is used to process JSON objects. Using this you can read or, write the contents of a JSON document using Java program.JSON-Simple maven dependencyFollowing is the maven dependency for the JSON-simple library − com.googlecode.json-simple json-simple ... Read More
The HTML DOM select add() method adds a new option to a drop-down list in an HTML document.SyntaxFollowing is the syntax −object.add(option, index)ExampleLet us see an example of HTML DOM select add() method − Live Demo html{ height:100%; } body{ text-align:center; color:#fff; background: radial-gradient( circle farthest-corner at 23.1% 64.6%, rgba(129, 125, 254, 1) 0%, rgba(111, 167, 254, 1) 90% ) no-repeat; height:100%; } p{ font-weight:700; font-size:1.1rem; } .drop-down{ ... Read More
Python functions can return multiple values. These values can be stored in variables directly. A function is not restricted to return a variable, it can return zero, one, two or more values.This is the default property of python to return multiple values/variables which is not available in many other programming languages like C++ or Java.For returning multiple values from a function, we can return tuple, list or dictionary object as per our requirement.Method 1: Using tupledef func(x): y0 = x+ 1 y1 = x * 3 y2 = y0 ** 3 return (y0, y1, y2)However, above ... Read More
The getColumnName() method of the ResultSetMetaData (interface) retrieves and returns the name of the specified column in the current ResultSet object.This method accepts an integer value representing the index of a column and, returns a String value representing the name of the specified column.To get the ResultSetMetaData object, you need to −Register the Driver: Select the required database register the Driver class of the particular database using the registerDriver() method of the DriverManager class or, the forName() method of the class named Class.DriverManager.registerDriver(new com.mysql.jdbc.Driver());Get connection: Create a connection object by passing the URL of the database, username and password of a ... Read More
Once you have installed JDK version on your windows machine, you have to set up Environment Variables.Please find below steps to set the java pathGo to My Computer ---> Right Click on it ---> Advanced System Settings ---> Advanced Tab ---> Click on Environment VariablesNow you have to alter the “Path” variable under system variables such that it contains a path to Java Environment. Select the path variable and click on the “Edit” buttonBy default, Java is installed in “C:\Program Files\Java\jre version\bin” in case you have changed the location of installation, then add that pathClick on OK button and now ... Read More
To add empty border to a component, use the BorderFactory class createEmptyBorder() method −Border emptyBorder = BorderFactory.createEmptyBorder(10, 10, 0, 0);To set the above border to a component, use the setBorder() method −JButton button = new JButton("Empty Border"); button.setBorder(emptyBorder);The following is an example to ad empty border to a JButton −Examplepackage my; import java.awt.BorderLayout; import java.awt.Color; import java.awt.Container; import javax.swing.BorderFactory; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.border.Border; import javax.swing.border.SoftBevelBorder; public class SwingDemo { public static void main(String args[]) { JFrame frame = new JFrame("Demo"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); Border raisedBorder = new SoftBevelBorder(SoftBevelBorder.RAISED, ... Read More
To create a Titleless and Borderless JFrame, use the setUndecorated() method and set it to TRUE −JFrame frame = new JFrame("Register!"); frame.setUndecorated(true);The following is an example to create a titleless and borderless JFrame −Examplepackage my; import java.awt.GridLayout; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPasswordField; import javax.swing.JTextField; import javax.swing.SwingConstants; public class SwingDemo { public static void main(String[] args) throws Exception { JFrame frame = new JFrame("Register!"); JLabel label1, label2, label3; frame.setLayout(new GridLayout(2, 2)); label1 = new JLabel("Id", SwingConstants.CENTER); label2 = new JLabel("Age", SwingConstants.CENTER); ... Read More
Use the $slice operator. Let us first create a collection with documents −> db.limitAndSliceProjectionDemo.insertOne( { "_id" : 101, "UserName" : "Carol", "UserAge" : 26, "UserMesssage" : [ "Hi", "Hello", "Bye", "Awesome", "Good", "Bad", "Nice", "Good Night", "Good Morning" ] } ); { "acknowledged" : true, "insertedId" : ... Read More
For this, you can use the DEFAULT CURRENT_TIMESTAMP clause in MySQL. Following is the syntax −CREATE TABLE yourTableName ( yourColumnName1 dataType1, yourColumnName timestamp DEFAULT CURRENT_TIMESTAMP );Let us first create a table −mysql> create table DemoTable -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> DueDate timestamp default current_timestamp -> ); Query OK, 0 rows affected (0.86 sec)Now you can insert some records in the table using insert command −mysql> insert into DemoTable values(); Query OK, 1 row affected (0.16 sec)Display all records from the table using select statement −mysql> select *from DemoTable;Output+----+---------------------+ ... Read More