AWS documentdb documentation change

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

File: documentdb/latest/developerguide/concatArrays.md

Summary

Added comprehensive documentation for the $concatArrays aggregation operator in Amazon DocumentDB, including syntax, parameters, MongoDB shell examples, and code examples in Node.js and Python

Security assessment

This change adds standard documentation for a MongoDB aggregation operator ($concatArrays) with no mention of security vulnerabilities, patches, or security-related fixes. The code examples show standard connection strings with TLS enabled, which is normal secure configuration but not a new security feature. The change appears to be routine documentation addition for a database feature.

Diff

diff --git a/documentdb/latest/developerguide/concatArrays.md b/documentdb/latest/developerguide/concatArrays.md
index 8b1378917..099abd71d 100644
--- a//documentdb/latest/developerguide/concatArrays.md
+++ b//documentdb/latest/developerguide/concatArrays.md
@@ -0,0 +1 @@
+[](/pdfs/documentdb/latest/developerguide/developerguide.pdf#concatArrays "Open PDF")
@@ -1,0 +3,156 @@
+[Documentation](/index.html)[Amazon DocumentDB](/documentdb/index.html)[Developer Guide](what-is.html)
+
+Example (MongoDB Shell)Code examples
+
+# $concatArrays
+
+The `$concatArrays` aggregation operator in Amazon DocumentDB is used to concatenate two or more arrays into a single array. This can be useful when you need to combine multiple arrays of data into a single array for further processing or analysis.
+
+**Parameters**
+
+  * `array1`: The first array to be concatenated.
+
+  * `array2`: The second array to be concatenated.
+
+  * `[array3, ...]`: (optional) Additional arrays to be concatenated.
+
+
+
+
+## Example (MongoDB Shell)
+
+The following example demonstrates how to use the `$concatArrays` operator to combine two arrays into a single array.
+
+**Create sample documents**
+    
+    
+    db.collection.insertMany([
+      {
+        "_id": 1,
+        "name": "John Doe",
+        "hobbies": ["reading", "swimming"],
+        "skills": ["programming", "design"]
+      },
+      {
+        "_id": 2,
+        "name": "Jane Smith",
+        "hobbies": ["hiking", "cooking"],
+        "skills": ["marketing", "analysis"]
+      }
+    ]);
+
+**Query example**
+    
+    
+    db.collection.aggregate([
+      {
+        $project: {
+          _id: 0,
+          name: 1,
+          all_activities: { $concatArrays: ["$hobbies", "$skills"] }
+        }
+      }
+    ]);
+
+**Output**
+    
+    
+    [
+      {
+        "name": "John Doe",
+        "all_activities": [
+          "reading",
+          "swimming",
+          "programming",
+          "design"
+        ]
+      },
+      {
+        "name": "Jane Smith",
+        "all_activities": [
+          "hiking",
+          "cooking",
+          "marketing",
+          "analysis"
+        ]
+      }
+    ]
+
+## Code examples
+
+To view a code example for using the `$concatArrays` 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('mydb');
+      const collection = db.collection('mycollection');
+    
+      const result = await collection.aggregate([
+        {
+          $project: {
+            _id: 0,
+            name: 1,
+            all_activities: { $concatArrays: ['$hobbies', '$skills'] }
+          }
+        }
+      ]).toArray();
+    
+      console.log(result);
+      client.close();
+    }
+    
+    example();
+
+Python
+    
+    
+    
+    from pymongo import MongoClient
+    
+    def example():
+        client = MongoClient('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false')
+        db = client['mydb']
+        collection = db['mycollection']
+    
+        result = list(collection.aggregate([
+            {
+                '$project': {
+                    '_id': 0,
+                    'name': 1,
+                    'all_activities': { '$concatArrays': ['$hobbies', '$skills'] }
+                }
+            }
+        ]))
+    
+        print(result)
+        client.close()
+    
+    example()
+
+![Warning](https://d1ge0kk1l5kms0.cloudfront.net/images/G/01/webservices/console/warning.png) **Javascript is disabled or is unavailable in your browser.**
+
+To use the Amazon Web Services Documentation, Javascript must be enabled. Please refer to your browser's Help pages for instructions.
+
+[Document Conventions](/general/latest/gr/docconventions.html)
+
+$concat
+
+$cond
+
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