AWS documentdb documentation change

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

File: documentdb/latest/developerguide/dateTrunc.md

Summary

Added new documentation page for the $dateTrunc aggregation operator in Amazon DocumentDB, including parameters, examples in MongoDB Shell, Node.js, and Python, and notes about version support

Security assessment

This change documents a new aggregation operator ($dateTrunc) for date manipulation in DocumentDB. The documentation includes functional examples and code samples but contains no references to security vulnerabilities, security fixes, or security features. The code examples show standard connection strings without any security-specific guidance beyond basic TLS parameters that are standard for DocumentDB connections.

Diff

diff --git a/documentdb/latest/developerguide/dateTrunc.md b/documentdb/latest/developerguide/dateTrunc.md
index 8b1378917..851152cac 100644
--- a//documentdb/latest/developerguide/dateTrunc.md
+++ b//documentdb/latest/developerguide/dateTrunc.md
@@ -0,0 +1 @@
+[](/pdfs/documentdb/latest/developerguide/developerguide.pdf#dateTrunc "Open PDF")
@@ -1,0 +3,163 @@
+[Documentation](/index.html)[Amazon DocumentDB](/documentdb/index.html)[Developer Guide](what-is.html)
+
+Example (MongoDB Shell)Code examples
+
+# $dateTrunc
+
+New from version 8.0
+
+Not supported by Elastic cluster.
+
+The `$dateTrunc` aggregation operator in Amazon DocumentDB truncates a date to a specified unit.
+
+**Parameters**
+
+  * `date`: A date expression that resolves to a date or timestamp.
+
+  * `unit`: A string that specifies the time unit for the subtrahend expression. Supported units are `year`, `quarter`, `month`, `week`, `day`, `hour`, `minute`, `second`, and `millisecond`.
+
+
+
+
+## Example (MongoDB Shell)
+
+The following example demonstrates how to use the `$dateTrunc` operator to truncate a date to to the hour.
+
+**Create sample documents**
+    
+    
+    db.events.insertMany([
+      {
+        eventName: "Event 1",
+        eventTime: ISODate("2025-04-01T12:15:00Z")
+      },
+      {
+        eventName: "Event 2",
+        eventTime: ISODate("2025-08-15T14:33:22Z")
+      },
+    ]);
+
+**Query example**
+    
+    
+    db.events.aggregate([
+      {
+        $project: {
+          eventName: 1,
+          eventTime: 1,
+          truncatedToHour: {
+            $dateTrunc: {
+              date: "$eventTime",
+              unit: "hour"
+            }
+          }
+        }
+      }
+    ]);
+
+**Output**
+    
+    
+    [
+      {
+        _id: ObjectId('6924a258d66dcae121d29515'),
+        eventName: 'Event 1',
+        eventTime: ISODate('2025-04-01T12:15:00.000Z'),
+        truncatedToHour: ISODate('2025-04-01T12:00:00.000Z')
+      },
+      {
+        _id: ObjectId('6924a258d66dcae121d29516'),
+        eventName: 'Event 2',
+        eventTime: ISODate('2025-08-15T14:33:22.000Z'),
+        truncatedToHour: ISODate('2025-08-15T14:00:00.000Z')
+      }
+    ]
+
+## Code examples
+
+To view a code example for using the `$dateTrunc` command, 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 events = db.collection('events');
+      
+      const result = await events.aggregate([
+        {
+          $project: {
+            eventName: 1,
+            eventTime: 1,
+            truncatedToHour: {
+              $dateTrunc: {
+                date: "$eventTime",
+                unit: "hour"
+              }
+            }
+          }
+        }
+      ]).toArray();
+      
+      console.log(result);
+      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']
+        events = db['events']
+        
+        result = list(events.aggregate([
+            {
+                "$project": {
+                    "eventName": 1,
+                    "eventTime": 1,
+                    "truncatedToHour": {
+                        "$dateTrunc": {
+                            "date": "$eventTime",
+                            "unit": "hour"
+                        }
+                    }
+                }
+            }
+        ]))
+        
+        print(result)
+        client.close()
+    
+    example()
+
+![Warning](https://d1ge0kk1l5kms0.cloudfront.net/images/G/01/webservices/console/warning.png) **Javascript is disabled or is unavailable in your browser.**
+
+To use the Amazon Web Services Documentation, Javascript must be enabled. Please refer to your browser's Help pages for instructions.
+
+[Document Conventions](/general/latest/gr/docconventions.html)
+
+$dateToString
+
+$dayOfMonth
+
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+
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+
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+
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