\nFROM mongo:7.0\nRUN openssl rand -base64 756 > \/etc\/mongo-keyfile \nRUN chmod 400 \/etc\/mongo-keyfile \nRUN chown mongodb:mongodb \/etc\/mongo-keyfile \n<\/pre><\/div>\n\n\ndocker-compose.yml:<\/strong><\/p>\n\n\n\n# From https:\/\/ginkcode.com\/post\/how-to-set-up-mongodb-with-replica-set-via-docker-compose\nversion: '3.8'\n \nservices:\n mongo:\n build:\n context: .\n dockerfile: Dockerfile\n container_name: mongodb-replicaset\n restart: always\n environment:\n MONGO_INITDB_ROOT_USERNAME: root\n MONGO_INITDB_ROOT_PASSWORD: root\n ports:\n - 27017:27017\n command: --replSet rs0 --keyFile \/etc\/mongo-keyfile --bind_ip_all --port 27017\n healthcheck:\n test: echo "try { rs.status() } catch (err) { rs.initiate({_id:'rs0',members:[{_id:0,host:'127.0.0.1:27017'}]}) }" | mongosh --port 27017 -u root -p root --authenticationDatabase admin\n interval: 5s\n timeout: 15s\n start_period: 15s\n retries: 10\n volumes:\n - data:\/data\/db\n \nvolumes:\n data: {}\n<\/pre><\/div>\n\n\nConnection string<\/strong><\/p>\n\n\n\nmongodb:\/\/root:root@localhost:27017\/?authSource=admin\n<\/pre><\/div>\n\n\nPlease visit Gink’s page <\/p>\n\n\n\n
Connecting to Qlik Replicate<\/h3>\n\n\n\n The great thing is that we don’t have to mess around installing extra ODBC drivers that can make the Qlik Replicate docker image complex.<\/p>\n\n\n\n
So with the MongoDB and the Qlik Replicate docker containers up and running; we can how create a new endpoint with the following settings:<\/p>\n\n\n\nField<\/strong><\/td>Variable<\/strong><\/td><\/tr>MongoDB Deployment<\/td> Standard<\/td><\/tr> Hosts<\/td> host.docker.internal<\/td><\/tr> Authentication Method<\/td> SCRAM-SHA-256<\/td><\/tr> Username<\/td> root<\/td><\/tr> Password<\/td> root<\/td><\/tr> Authentication database name<\/td> admin<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\nA test connection confirmed that the connection was working as expected.<\/p>\n\n\n\n
Proving that deletes are working<\/h2>\n\n\n\n Getting close to resolving the burden of proof.\u00a0 I got our GenAI to create a simple python script to add, update, and delete some data from the Mongo Database and set it running:<\/p>\n\n\n
\nimport pymongo\nimport random\nimport string\nimport time\n\ndef generate_random_string(length=10):\n """Generate a random string of fixed length."""\n letters = string.ascii_lowercase\n return ''.join(random.choice(letters) for i in range(length))\n\ndef add_random_data(collection):\n """Adds a new document with random data to the collection."""\n \n new_document = {\n "name": generate_random_string(),\n "age": random.randint(18, 99),\n "email": f"{generate_random_string(5)}@example.com"\n }\n \n result = collection.insert_one(new_document)\n\n print(f"Added: {result.inserted_id}")\n\ndef update_random_data(collection):\n """Updates a random document in the collection."""\n if collection.count_documents({}) > 0:\n # Get a random document using the $sample aggregation operator\n try:\n random_doc_cursor = collection.aggregate([{"$sample": {"size": 1}}])\n random_doc = next(random_doc_cursor)\n new_age = random.randint(18, 99)\n \n collection.update_one(\n {"_id": random_doc["_id"]},\n {"$set": {"age": new_age}}\n )\n\n print(f"Updated: {random_doc['_id']} with new age {new_age}")\n except StopIteration:\n print("Could not find a document to update.")\n else:\n print("No documents to update.")\n\ndef delete_random_data(collection):\n """Deletes a random document from the collection."""\n if collection.count_documents({}) > 0:\n # Get a random document using the $sample aggregation operator\n try:\n random_doc_cursor = collection.aggregate([{"$sample": {"size": 1}}])\n random_doc = next(random_doc_cursor)\n\n collection.delete_one({"_id": random_doc["_id"]})\n \n print(f"Deleted: {random_doc['_id']}")\n except StopIteration:\n print("Could not find a document to delete.")\n else:\n print("No documents to delete.")\n\n\nif __name__ == "__main__":\n print("Starting script... Press Ctrl+C to stop.")\n\n try:\n client = pymongo.MongoClient("mongodb:\/\/root:root@localhost:27017\/?authSource=admin")\n db = client["random_data_db"]\n collection = db["my_collection"]\n # The ismaster command is cheap and does not require auth.\n client.admin.command('ismaster')\n print("MongoDB connection successful.")\n except pymongo.errors.ConnectionFailure as e:\n print(f"Could not connect to MongoDB: {e}")\n exit()\n\n while True:\n try:\n add_random_data(collection)\n add_random_data(collection)\n add_random_data(collection)\n\n update_random_data(collection)\n delete_random_data(collection)\n \n # Wait for five seconds before the next cycle\n time.sleep(5)\n\n except KeyboardInterrupt:\n print("\\nScript stopped by user.")\n break\n except Exception as e:\n print(f"An error occurred: {e}")\n break\n\n # Close the connection\n client.close()\n print("MongoDB connection closed.")\n\n<\/pre><\/div>\n\n\nWith the script running and adding, updating and deleting data to the MongoDB; a QR task can be created to read from the database “random_data_db” and collection “my_collection”<\/p>\n\n\n\n
And voil\u00e0. Data is flowing through Qlik Replicate from the MongoDB.<\/p>\n\n\n\n
And more importantly deletes are getting picked up as expected.<\/p>\n\n\n\n <\/p>\n\n\n
\n{\n\t"header__change_seq":"20260204052516000000000000000004085",\n\t"header__change_oper":"D","header__change_mask":"80",\n\t"header__stream_position":"6982d83c:00000005:00000000",\n\t"header__operation":"DELETE",\n\t"header__transaction_id":"4155544F434F4D4D4954000000000000",\n\t"header__timestamp":"2026-02-04 05:25:16.000000",\n\t"_id":"6982d8186b2cc5ee1a161d13",\n\t"_doc":"{\\"_id\\": {\\"$oid\\": \\"6982d8186b2cc5ee1a161d13\\"}}"\n}\n \n<\/pre><\/div>\n\n\nConclusion <\/h2>\n\n\n\n And voil\u00e0. Data is flowing through Qlik Replicate from the MongoDB.<\/p>\n\n\n\n
And more importantly; deletes are getting picked up as expected.<\/p>\n\n\n\n
If you have come to my humble website after googling \u201cCan Qlik Replicate replicate deletes from a MongoDB?\u201d well, the answer is \u201cYes \u2013 Yes it can.\u201d<\/p>\n\n\n\n
I can only speculate where that rumour came from. Maybe it was from an older version of QR or MongoDB that the person in question was referring to? Or some very abnormal setup of a MongoDB cluster?<\/p>\n\n\n\n
Or some complete misunderstanding.<\/p>\n\n\n\n
Anyway, I have meeting in the next hour or two with the project team; let us find out.<\/p>\n","protected":false},"excerpt":{"rendered":"
That message from my Manager I got a message from my manager unexpectedly. \u201cHey. A team is converting a MSSQL database to MongoDB. Can Qlik Replicate...<\/p>\n","protected":false},"author":1,"featured_media":1720,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[103,16],"tags":[104,36],"class_list":["post-1719","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-mongodb","category-qlik-replicate","tag-mongodb","tag-qlikreplicate"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t
![\"\"](\"https:\/\/craftcookcode.com\/wp-content\/uploads\/2026\/02\/code_qr_mongo_02-1024x968.png\")
<\/figure>\n\n\n\n![\"\"](\"https:\/\/craftcookcode.com\/wp-content\/uploads\/2026\/02\/code_qr_mongo_03-1024x312.png\")
<\/figure>\n\n\n\n