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
MongoDB multidimensional array projection?
For MongoDB multidimensional array projection, you need to use aggregate framework. Let us first create a collection with documents. Here, we have multidimensional array for Student marks −
> db.multiDimensionalArrayProjection.insertOne(
... {
... "StudentFirstName" : "Chris",
... "StudentMarks" : [ [98, 99],[56,79] ]
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5cc6b75a9cb58ca2b005e66c")
}Following is the query to display all documents from a collection with the help of find() method −
> db.multiDimensionalArrayProjection.find().pretty();
This will produce the following output −
{
"_id" : ObjectId("5cc6b75a9cb58ca2b005e66c"),
"StudentFirstName" : "Chris",
"StudentMarks" : [
[
98,
99
],
[
56,
79
]
]
}Following is the query for MongoDB multidimensional array projection −
> db.multiDimensionalArrayProjection.aggregate([
... { $unwind: '$StudentMarks' },
... { $limit: 1 },
... { $project: { _id: 0, StudentMarks: 1 } },
... { $unwind: '$StudentMarks' },
... { $skip: 1 },
... { $limit: 1 }
... ]);This will produce the following output −
{ "StudentMarks" : 99 }
Updated on: 30-Jul-2019
479 Views
Advertisements