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

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" : [          {     ... Read More

Here we will see the kbhit functionality in C. The kbhit is basically the Keyboard Hit. This function is present at conio.h header file. So for using this, we have to include this header file into our code.The functionality of kbhit() is that, when a key is pressed it returns ... Read More

In C++ we can use the function overloading feature. Using this feature, we can create functions with same name. The only difference is the type of the arguments, and the number of arguments. The return type is not considered here. Now the question comes how the C++ distinguishes overloaded functions ... Read More

To apply adjustments to the last column only, use the setAutoResizeMode and set the mode. The mode here would be AUTO_RESIZE_LAST_COLUMN. This will allow you to adjust only the last columns even if any of the column header is dragged to resize.Let us first see an example to create a ... Read More

While creating a table, in certain scenarios, we need values to column such as ID, to be generated/incremented automatically. Various databases support this feature in different ways.In MySQL database you can declare a column auto increment using the following syntax.CREATE TABLE table_name(    ID INT PRIMARY KEY AUTO_INCREMENT,    column_name1 ... Read More

To access subdocument value, let us first create a collection with documents −> db.accessSubDocumentDemo.insertOne( ...    { ... ...       "Details" : { ...          "1" : { ...             "StudentLowerScore" : "33", ...             ... Read More

While creating a table, in certain scenarios, we need values to column such as ID, to be generated/incremented automatically. Various databases support this feature in different ways.In MySQL database you can declare a column auto increment using the following syntax.CREATE TABLE table_name(    ID INT PRIMARY KEY AUTO_INCREMENT,    column_name1 ... Read More