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Articles by Nishtha Thakur
Page 25 of 40
How to update _id field in MongoDB?
You can’t directly update _id field i.e. write some script to update. Let us first create a collection with documents −> db.updatingIdFieldDemo.insertOne({"StudentName":"Chris"}); { "acknowledged" : true, "insertedId" : ObjectId("5ce271bb36e8b255a5eee949") }Following is the query to display all documents from a collection with the help of find() method −> db.updatingIdFieldDemo.find();This will produce the following output −{ "_id" : ObjectId("5ce271bb36e8b255a5eee949"), "StudentName" : "Chris" }Following is the query to update _id field in MongoDB −> var myDocument=db.updatingIdFieldDemo.findOne({StudentName:"Chris"}); > myDocument._id = 101; 101 > db.updatingIdFieldDemo.save(myDocument); WriteResult({ "nMatched" : 0, "nUpserted" : 1, "nModified" : 0, "_id" : 101 }) > db.updatingIdFieldDemo.remove({_id:ObjectId("5ce271bb36e8b255a5eee949")}); WriteResult({ ...
Read MoreInsert multiple sets of values in a single statement with MySQL?
Let us first create a table −mysql> create table DemoTable ( UserId int, UserName varchar(20), UserAge int ); Query OK, 0 rows affected (0.53 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(UserId,UserName,UserAge) values(100,'John',25),(101,'Larry',24),(102,'Chris',22),(103,'Carol',27); Query OK, 4 rows affected (0.16 sec) Records: 4 Duplicates: 0 Warnings: 0Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+--------+----------+---------+ | UserId | UserName | UserAge | +--------+----------+---------+ | 100 | John | 25 | | 101 | Larry | 24 | | 102 | Chris | 22 | | 103 | Carol | 27 | +--------+----------+---------+ 4 rows in set (0.00 sec)
Read MoreI want to highlight all the text in the Java Swing Control Text Pane
To highlight all the text, use the selectAll() method of the JTextPane component −JTextPane pane = new JTextPane(); pane.selectAll();The following is an example to highlight the JTextPane text. Here, we are displaying a code in the JTextPane and highlighting it −Examplepackage my; import java.awt.BorderLayout; import java.awt.Container; import javax.swing.JFrame; import javax.swing.JScrollPane; import javax.swing.JTextPane; import javax.swing.text.BadLocationException; public class SwingDemo { public static void main(String args[]) throws BadLocationException { JFrame frame = new JFrame("Demo"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); Container container = frame.getContentPane(); JTextPane pane = new JTextPane(); pane.setContentType("text/html"); ...
Read MoreMongoDB query to remove empty objects in an object-array?
You can use $pull operator for this. Let us first create a collection with documents. Here, we have also added an empty object −> db.removeEmptyObjectsDemo.insertOne( { "_id" :101, "LoginDate" :new ISODate(), "UserDetails" : [ { "UserName" : "John" }, { }, { "UserName" : "Sam" } ] } ); { ...
Read MoreMongoDB query to update an array element matching a condition using $push?
Let us first create a collection with documents −> db.updateArrayElementDemo.insertOne( { "UserDetails": [ { "UserName":"Chris", "UserAge":23 } ] } ); { "acknowledged" : true, "insertedId" : ObjectId("5ce9029378f00858fb12e90d") }Following is the query to display all documents from a collection with the help of find() method −> db.updateArrayElementDemo.find().pretty();This will produce the following output −{ "_id" : ObjectId("5ce9029378f00858fb12e90d"), "UserDetails" : [ { ...
Read MoreUpdating boolean value in MySQL?
To update boolean value, you can use SET. Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, isMarried boolean ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(isMarried) values(false); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable(isMarried) values(true); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(isMarried) values(true); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(isMarried) values(false); Query OK, 1 row affected (0.13 sec)Display all records ...
Read MoreFind documents where all elements of an array have a specific value in MongoDB?\\n
You can use find() for this. Let us first create a collection with documents −> db.findDocumentsDemo.insertOne( { _id: 101, "ProductDetails": [ { "ProductValue":100 }, { "ProductValue":120 } ] } ); { "acknowledged" : true, "insertedId" : 101 } > db.findDocumentsDemo.insertOne( { _id: 102, "ProductDetails": [ { "ProductValue":120}, { "ProductValue":120 }, { "ProductValue":120 } ] } ); { "acknowledged" ...
Read MorePerforming mathematical operations in MySQL IF then ELSE is possible?
For performing mathematical operations and working with conditions, you can consider CASE statement. Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, FruitName varchar(100), FruitPrice int ); Query OK, 0 rows affected (0.26 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(FruitName, FruitPrice) values('Orange', 250); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable(FruitName, FruitPrice) values('Banana', 100); Query OK, 1 row affected (0.05 sec) mysql> insert into DemoTable(FruitName, FruitPrice) values('Apple', 150); Query OK, 1 row affected (0.05 sec) ...
Read MoreConvert a field to an array using MongoDB update operation?
To convert a field to an array, use $set operator. Let us first create a collection with documents −> db.convertAFieldToAnArrayDemo.insertOne({"StudentSubject":"MongoDB"}); { "acknowledged" : true, "insertedId" : ObjectId("5ce92d7778f00858fb12e91d") }Following is the query to display all documents from a collection with the help of find() method −> db.convertAFieldToAnArrayDemo.find();This will produce the following output −{ "_id" : ObjectId("5ce92d7778f00858fb12e91d"), "StudentSubject" : "MongoDB" }Following is the query to convert a field to an array using update operation with $set:−> db.convertAFieldToAnArrayDemo.find().forEach(function(myDocument) { db.convertAFieldToAnArrayDemo.update( { _id: myDocument._id }, { "$set": { "StudentSubject": [myDocument.StudentSubject] } } ); })Let ...
Read MoreAdding new column after a specific column and defining a default in MySQL?
You need to follow some steps to add a new column after a specific column and defining default value. In order to achieve this, you need to use ALTER command. Let us first create a table −mysql> create table DemoTable ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentFirstName varchar(20), StudentAge int, StudentCountryName varchar(100) ); Query OK, 0 rows affected (0.21 sec)Let us check the description of table −mysql> desc DemoTable;This will produce the following output −+--------------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | ...
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