Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
How to loop through collections with a cursor in MongoDB?
Following is the syntax to loop through collections with cursor
var anyVariableName1;
var anyVariableName2= db.yourCollectionName.find();
while(yourVariableName2.hasNext()) {
yourVariableName1= yourVariableName2.next(); printjson(yourVariableName1);
};Let us create a collection with documents. Following is the query
> db.loopThroughCollectionDemo.insertOne({"StudentName":"John","StudentAge":23});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c9ca81f2d6669774125247f")
}
> db.loopThroughCollectionDemo.insertOne({"StudentName":"Larry","StudentAge":21});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c9ca8272d66697741252480")
}
> db.loopThroughCollectionDemo.insertOne({"StudentName":"Chris","StudentAge":25});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c9ca8462d66697741252481")
}
> db.loopThroughCollectionDemo.insertOne({"StudentName":"Robert","StudentAge":24});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c9ca8632d66697741252482")
}Following is the query to display all documents from a collection with the help of find() method
> db.loopThroughCollectionDemo.find().pretty();
This will produce the following output
{
"_id" : ObjectId("5c9ca81f2d6669774125247f"),
"StudentName" : "John",
"StudentAge" : 23
}
{
"_id" : ObjectId("5c9ca8272d66697741252480"),
"StudentName" : "Larry",
"StudentAge" : 21
}
{
"_id" : ObjectId("5c9ca8462d66697741252481"),
"StudentName" : "Chris",
"StudentAge" : 25
}
{
"_id" : ObjectId("5c9ca8632d66697741252482"),
"StudentName" : "Robert",
"StudentAge" : 24
}Following is the query to loop through collections with cursor
> var allDocumentValue;
> var collectionName=db.loopThroughCollectionDemo.find();
> while(collectionName.hasNext()){allDocumentValue= collectionName.next();printjson(allDocumentValue);
... }This will produce the following output
{
"_id" : ObjectId("5c9ca81f2d6669774125247f"),
"StudentName" : "John",
"StudentAge" : 23
}
{
"_id" : ObjectId("5c9ca8272d66697741252480"),
"StudentName" : "Larry",
"StudentAge" : 21
}
{
"_id" : ObjectId("5c9ca8462d66697741252481"),
"StudentName" : "Chris",
"StudentAge" : 25
}
{
"_id" : ObjectId("5c9ca8632d66697741252482"),
"StudentName" : "Robert",
"StudentAge" : 24
}
Updated on: 30-Jul-2019
1K+ Views
Advertisements