To limit the records in MongoDB, you would like touse limit() method. The method accepts one number type argument, which is the number of documents that you want to be displayed.
Syntax
The basic syntax of limit() method is as follows −
>db.COLLECTION_NAME.find().limit(NUMBER)
Example
Consider the collection myycol has the subsequent data.
{ “_id” : ObjectId(5983548781331adf45ec5), “title”:”MongoDB Overview”}
{ “_id” : ObjectId(5983548781331adf45ec6), “title”:”NoSQL Overview”}
{ “_id” : ObjectId(5983548781331adf45ec7), “title”:”Tecklearn Overview”}
Subsequent example will display only two documents while querying the document.
>db.mycol.find({},{“title”:1,_id:0}).limit(2)
{“title”:”MongoDB Overview”}
{“title”:”NoSQL Overview”}
>
If you don’t specify the number argument in limit() method then it will display all documents from the collection.

MongoDB Skip() Method

Apart from limit() method, there is one more method skip() which also accepts number type argument and is used to skip the number of documents.
Syntax
The basic syntax of skip() method is as follows −
>db.COLLECTION_NAME.find().limit(NUMBER).skip(NUMBER)
Example
Subsequent example will display only the second document.
>db.mycol.find({},{“title”:1,_id:0}).limit(1).skip(1)
{“title”:”NoSQL Overview”}
>
Please note, the default value in skip() method is 0.

MongoDB – Projection

In MongoDB, projection means selecting only the required data rather than selecting whole of the data of a document. If a document has 5 fields and you would like toshow only 3, then select only 3 fields from them.

The find() Method

MongoDB’s find() method, explained in MongoDB Query Document accepts second optional parameter that is list of fields that you want to retrieve. In MongoDB, when you execute find() method, then it displays all fields of a document. To limit this, you would like toset a list of fields with value 1 or 0. 1 is used to show the field while 0 is used to hide the fields.
Syntax
The basic syntax of find() method with projection is as follows −
>db.COLLECTION_NAME.find({},{KEY:1})
Example
Consider the collection mycol has the subsequent data −
{ “_id” : ObjectId(5983548781331adf45ec5), “title”:”MongoDB Overview”}
{ “_id” : ObjectId(5983548781331adf45ec6), “title”:”NoSQL Overview”}
{ “_id” : ObjectId(5983548781331adf45ec7), “title”:”Tecklearn Overview”}
Subsequent example will display the title of the document while querying the document.
>db.mycol.find({},{“title”:1,_id:0})
{“title”:”MongoDB Overview”}
{“title”:”NoSQL Overview”}
{“title”:”Tecklearn Overview”}
>
Please note _id field is always displayed while executing find() method, if you don’t want this field, then you would like to set it as 0.
So, this brings us to the end of blog. This Tecklearn ‘How to limit records using MongoDB and use projection in MongoDB’ helps you with commonly asked questions if you are looking out for a job in MongoDB and No-SQL Database Domain.
If you wish to learn and build a career in MongoDB or No-SQL Database domain, then check out our interactive, MongoDB Training, that comes with 24*7 support to guide you throughout your learning period. Please find the link for course details:

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About the Course

Tecklearn’s MongoDB Training helps you to master the NoSQL database. The course makes you job-ready by letting you comprehend schema design, data modelling, replication, and query with MongoDB through real-time examples. Along with this, you’ll also gain hands-on expertise in installing, configuring, and maintaining the MongoDB environment, including monitoring and operational strategies from this online MongoDB training. Upon completion of this online training, you will hold a solid understanding and hands-on experience with MongoDB.

Why Should you take MongoDB Training?

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What you will Learn in this Course?

Introduction to MongoDB and Importance of NoSQL
• Understanding the basic concepts of RDBMS
• What is NoSQL Database and its significance?
• Challenges of RDBMS and How NoSQL suits Big Data needs
• Types of NoSQL Database and NoSQL vs. SQL Comparison
• CAP Theorem and Implementing NoSQL
• Introduction to MongoDB and its advantages
• Design Goals for MongoDB Server and Database, MongoDB tools
• Collection, Documents and Key Value Pair
• Introduction to JSON and BSON documents
• MongoDB installation
MongoDB Installation
• MongoDB Installation
• Basic MongoDB commands and operations,
• Mongo Chef (MongoGUI) Installation
Schema Design and Data Modelling
• Why Data Modelling?
• Data Modelling Approach
• Data Modelling Concepts
• Difference between MongoDB and RDBMS modelling
• Challenges for Data Modelling
• Model Relationships between Documents
• Data Model Examples and Patterns
• Model Tree Structures
CRUD Operations
• MongoDB Architecture
• CRUD Introduction and MongoDB CRUD Concepts
• MongoDB CRUD Concerns (Read and Write Operations)
• Cursor Query Optimizations and Query Behaviour in MongoDB
• Distributed Read and Write Queries
• MongoDB Datatypes
Indexing and Aggregation Framework
• Concepts of Data aggregation and types and data indexing concepts
• Introduction to Aggregation
• Approach to Aggregation
• Types of Aggregation: Pipeline, MapReduce and Single Purpose
• Performance Tuning
MongoDB Administration
• Administration concepts in MongoDB
• MongoDB Administration activities: Health check, recovery, backup, database sharing and profiling, performance tuning etc.
• Backup and Recovery Methods for MongoDB
• Export and Import of Data from MongoDB
• Run time configuration of MongoDB
MongoDB Security
• Security Introduction
• MongoDB security Concepts and security approach
• MongoDB integration with Java and Robomongo
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