Let us first create a collection with documents −> db.projectionAnElementDemo.insertOne( ...    { ...       "CustomerId":100, ...       "CustomerDetails": [ ...          { ...             "CustomerName": "Chris", ...             "CustomerCountryName": "US" ...   ... Read More

You need to use multi:true to update multiple documents. Let us first create a collection with documents −> db.multiUpdateDemo.insertOne({"ClientName":"John", "ClientAge":29}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cda5bc0b50a6c6dd317adc8") } > db.multiUpdateDemo.insertOne({"ClientName":"Carol", "ClientAge":31}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cda5bc1b50a6c6dd317adc9") } > db.multiUpdateDemo.insertOne({"ClientName":"John", "ClientAge":39}); {    "acknowledged" : ... Read More

In the cstdlib library of C++, there are different functions for getting the absolute value except from abs. The abs are used basically for int type input in C, and int, long, long long in C++. The others are used for long, and long long type data etc. Let us ... Read More

Here we will see how to prevent inheritance in C++. The concept of preventing the inheritance is known as final class.In Java or C#, we can use final classes. In C++ there are no such direct way. Here we will see how to simulate the final class in C++.Here we ... Read More

To highlight a row in a table, you can use the addRowSelectionInterval() method. At first create a table −DefaultTableModel tableModel = new DefaultTableModel(); JTable table = new JTable(tableModel);Add some columns −tableModel.addColumn("Language/ Technology"); tableModel.addColumn("Text Tutorial"); tableModel.addColumn("Video Tutorial"); tableModel.addColumn("Views");Now, add rows to the table −tableModel.addRow(new Object[] { "NodeJS", "No", "Yes", "2350"}); tableModel.addRow(new ... Read More

If you will try to use the method drop(), then it will delete all information about the collection. Indexing is fast. However, if you will use the method remove(), then it removes all records but keeps the collection and indexes.Let us check with the help of example.Using drop()Let us first ... Read More

We use gcc and g++ compilers in different times. Here we will see what are the differences between gcc and g++.The gcc is GNU C compiler, and g++ is GNU C++ compiler. The main differences are like below −gcc can compile *.c or *.cpp files as C and C++ respectivelyg++ ... Read More

You can use $match operator under aggregate() to get the first record. Let us first create a collection with documents −> db.conditionalFirstDemo.insertOne({_id:100, "StudentName":"Chris", "StudentSubject":null}); { "acknowledged" : true, "insertedId" : 100 } > db.conditionalFirstDemo.insertOne({_id:101, "StudentName":"Chris", "StudentSubject":null}); { "acknowledged" : true, "insertedId" : 101 } >db.conditionalFirstDemo.insertOne({_id:102, "StudentName":"Chris", "StudentSubject":"MongoDB"}); { "acknowledged" : ... 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 ... Read More

In this section, we will see how to find the middle of three given values by comparing them. So if three numbers are given like (10, 30, 20), then it will find 20 as this is the middle element. Let us see the algorithm first, then we will implement that ... Read More