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
Retrieving the first document in a MongoDB collection?
To retrieve the first document in a collection, you can use findOne(). Following is the syntax
var anyVariableName=db.yourCollectionName.findOne(); //To print result at MongoDB console write the variable name yourVariableName
Let us first create a collection with documents
> db.retrieveFirstDocumentDemo.insertOne({"ClientName":"Robert","ClientAge":23});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ca2325966324ffac2a7dc6d")
}
> db.retrieveFirstDocumentDemo.insertOne({"ClientName":"Chris","ClientAge":26});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ca2326266324ffac2a7dc6e")
}
> db.retrieveFirstDocumentDemo.insertOne({"ClientName":"Larry","ClientAge":29});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ca2326a66324ffac2a7dc6f")
}
> db.retrieveFirstDocumentDemo.insertOne({"ClientName":"David","ClientAge":39});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ca2327566324ffac2a7dc70")
}Following is the query to display all documents from a collection with the help of find() method
> db.retrieveFirstDocumentDemo.find().pretty();
This will produce the following output
{
"_id" : ObjectId("5ca2325966324ffac2a7dc6d"),
"ClientName" : "Robert",
"ClientAge" : 23
}
{
"_id" : ObjectId("5ca2326266324ffac2a7dc6e"),
"ClientName" : "Chris",
"ClientAge" : 26
}
{
"_id" : ObjectId("5ca2326a66324ffac2a7dc6f"),
"ClientName" : "Larry",
"ClientAge" : 29
}
{
"_id" : ObjectId("5ca2327566324ffac2a7dc70"),
"ClientName" : "David",
"ClientAge" : 39
}Following is the query to retrieve first document in a collection
> var firstDocumentOnly=db.retrieveFirstDocumentDemo.findOne(); > firstDocumentOnly;
This will produce the following output
{
"_id" : ObjectId("5ca2325966324ffac2a7dc6d"),
"ClientName" : "Robert",
"ClientAge" : 23
}
Updated on: 30-Jul-2019
2K+ Views
Advertisements