- Trending Categories
- 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
Convert 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 us check the document once again −
> db.convertAFieldToAnArrayDemo.find();
This will produce the following output −
{ "_id" : ObjectId("5ce92d7778f00858fb12e91d"), "StudentSubject" : [ "MongoDB" ] }
Advertisements