AWS documentdb documentation change

Service: documentdb · 2026-03-31 · Documentation low

File: documentdb/latest/developerguide/dollar-projection.md

Summary

Added comprehensive documentation for the $ projection operator in Amazon DocumentDB, including syntax, parameters, examples in MongoDB Shell, Node.js, and Python, along with code samples and usage instructions.

Security assessment

This is a new documentation page for a MongoDB query operator feature. The content is purely functional documentation about how to use the $ projection operator. There is no security context, vulnerability disclosure, or security feature documentation included in the changes.

Diff

diff --git a/documentdb/latest/developerguide/dollar-projection.md b/documentdb/latest/developerguide/dollar-projection.md
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+++ b//documentdb/latest/developerguide/dollar-projection.md
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+[](/pdfs/documentdb/latest/developerguide/developerguide.pdf#dollar-projection "Open PDF")
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+[Documentation](/index.html)[Amazon DocumentDB](/documentdb/index.html)[Developer Guide](what-is.html)
+
+Example (MongoDB Shell)Code examples
+
+# $
+
+The `$` projection operator limits the contents of an array field to return only the first element that matches the query condition. It is used to project a single matching array element.
+
+**Parameters**
+
+  * `field.$`: The array field with the positional operator to project the first matching element.
+
+
+
+
+## Example (MongoDB Shell)
+
+The following example demonstrates using the `$` projection operator to return only the matching array element.
+
+**Create sample documents**
+    
+    
+    db.students.insertMany([
+      { _id: 1, name: "Alice", grades: [85, 92, 78, 95] },
+      { _id: 2, name: "Bob", grades: [70, 88, 92, 65] },
+      { _id: 3, name: "Charlie", grades: [95, 89, 91, 88] }
+    ]);
+
+**Query example**
+    
+    
+    db.students.find(
+      { grades: { $gte: 90 } },
+      { name: 1, "grades.$": 1 }
+    );
+
+**Output**
+    
+    
+    { "_id" : 1, "name" : "Alice", "grades" : [ 92 ] }
+    { "_id" : 2, "name" : "Bob", "grades" : [ 92 ] }
+    { "_id" : 3, "name" : "Charlie", "grades" : [ 95 ] }
+
+In this example, only the first grade that is greater than or equal to 90 is returned for each student.
+
+## Code examples
+
+To view a code example for using the `$` projection operator, choose the tab for the language that you want to use:
+
+Node.js
+    
+    
+    
+    const { MongoClient } = require('mongodb');
+    
+    async function example() {
+      const client = await MongoClient.connect('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false');
+      const db = client.db('test');
+      const collection = db.collection('students');
+    
+      const result = await collection.find(
+        { grades: { $gte: 90 } },
+        { projection: { name: 1, "grades.$": 1 } }
+      ).toArray();
+    
+      console.log(JSON.stringify(result, null, 2));
+      await client.close();
+    }
+    
+    example();
+
+Python
+    
+    
+    
+    from pymongo import MongoClient
+    
+    def example():
+        client = MongoClient('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false')
+        db = client['test']
+        collection = db['students']
+    
+        result = list(collection.find(
+            {'grades': {'$gte': 90}},
+            {'name': 1, 'grades.$': 1}
+        ))
+    
+        print(result)
+        client.close()
+    
+    example()
+
+![Warning](https://d1ge0kk1l5kms0.cloudfront.net/images/G/01/webservices/console/warning.png) **Javascript is disabled or is unavailable in your browser.**
+
+To use the Amazon Web Services Documentation, Javascript must be enabled. Please refer to your browser's Help pages for instructions.
+
+[Document Conventions](/general/latest/gr/docconventions.html)
+
+Query and projection operators
+
+$all
+
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