VEDANT PATIL - BCA2302100

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Sorting and Limiting Data in Aggregation - VEDANT PATIL

1. Introduction to the Topic

MongoDB is a powerful NoSQL database known for its flexibility, scalability, and support for rich queries. One of its most powerful features is the aggregation framework, which allows developers to perform complex data operations, such as filtering, grouping, projecting, sorting, and limiting results.

In my blog, there will be focus on sorting and limiting data using MongoDB aggregation pipeline — essential techniques for optimizing queries and retrieving the most relevant data from large datasets.

 

2.  Explanation

The aggregation framework in MongoDB works by passing documents through a sequence of stages, each performing a specific operation. Two important stages in this pipeline are:

 

$sort: Orders the documents based on one or more fields.

 

$limit: Restricts the number of documents returned.

 

* Syntax Overview

db.collection.aggregate([

{ $sort: { field_name: 1 or -1 } },   // 1 for ascending, -1 for descending

  { $limit: number }                    // Number of documents to return

]);

 

3. Procedure

Let's go through a step-by-step procedure using an example :

 

* Objective : Find top 3 highest scoring students from a students collection.

✅ Step 1: Sample Data

[

  { "name": "Alice", "score": 85 },

  { "name": "Bob", "score": 92 },

  { "name": "Charlie", "score": 78 },

  { "name": "David", "score": 90 },

  { "name": "Eve", "score": 95 }

]

✅ Step 2: Aggregation Pipeline

db.students.aggregate([

  { $sort: { score: -1 } },   // Sort by score in descending order

  { $limit: 3 }               // Return only top 3 documents

]);

✅ Step 3: Output

[

  { "name": "Eve", "score": 95 },

  { "name": "Bob", "score": 92 },

  { "name": "David", "score": 90 }

]

 

4. Screenshot

Inserting Sample Data

Explanation : Inserts 5 student records into the students collection.

 

Sorting Only

Explanation : Sorts students by their score in descending order using $sort.

 

Limiting Only

Explanation : Returns only the first 2 documents from the collection using $limit.

 

Pagination with $skip and $limit

Explanation : Implements basic pagination by skipping 2 records and limiting the next 2 results.

 

5. Future Scope

Sorting and limiting data is not just limited to simple queries — it forms the backbone of data analytics, leaderboards, real-time dashboards, and search engines. Here's what the future holds :

 

* Performance Optimization : More intelligent indexing and sorting for faster big data handling.

* AI Integration : Sorted/limited results can feed directly into machine learning pipelines.

* Cloud Scaling : Use of $sort + $limit in MongoDB Atlas for global-scale applications.

* Visualization Tools : Sorted/limited aggregations will power visualization dashboards (e.g., charts, reports).

* Advanced Use Cases : Pagination, infinite scrolling, and time-series data processing.

VEDANT PATIL

University : Sri Balaji University, Pune

School : School of Computer Studies

Course : BCA (Bachelor of Computer Applications)

Interests : NoSQL, MongoDB, and related technologies

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