Debunking Common MongoDB Myths: A Comprehensive Guide

The author, after less than a year of hands‑on experience with MongoDB, noticed many outdated myths circulating online and decided to clarify them in a structured article.

Myth 0: MongoDB is web‑scalable. Early videos featuring a mascot are now obsolete; MongoDB’s scalability depends on replica sets and proper hardware, not a magical web‑scale claim.

Myth 1: What is MongoDB? MongoDB is a distributed document database that uses replica sets for redundancy. Clients normally connect to the primary node, while secondaries hold full copies of the data.

Myth 2: MongoDB version is 3.2. Installing via apt‑get mongodb on older Debian releases still gives the outdated 3.2 series. The current stable release (as of 2020) is 4.4, and Atlas provides a managed DBaaS option.

Myth 3: MongoDB is a JSON database. MongoDB stores data as BSON, a binary superset of JSON that supports additional types such as dates, binary data, and geospatial objects, offering better performance and richer typing.

Myth 4: MongoDB does not support transactions. MongoDB is ACID‑compliant for single‑document operations, and since version 4.0 it supports multi‑document transactions (4.2 adds sharded‑cluster transactions), though they incur performance costs.

Myth 5: MongoDB cannot model relationships. The aggregation pipeline enables powerful joins across collections, and MongoDB has supported lookups since version 2.2.

Myth 6: MongoDB is all about sharding. Sharding distributes data across replica sets but requires a minimum of eight servers for a basic cluster. Often, scaling hardware is a simpler solution, and Atlas can handle automatic scaling.

Myth 7: MongoDB is insecure. Modern MongoDB defaults disable unauthenticated network access, support TLS encryption, SCRAM‑SHA‑256 authentication, and client‑side field‑level encryption, mitigating many historical security issues.

Myth 8: MongoDB loses data. Large enterprises (banks, publishers) rely on MongoDB without reported massive data loss; proper backups and replica set configurations prevent data loss.

Myth 9: MongoDB is just a toy. MongoDB is a production‑grade, general‑purpose document store with atomic updates, rich query language, sharding, change streams, and advanced security features.

Example document fetched via PyMongo (shown unchanged):

{
    '_id': ObjectId('573a1390f29313caabcd4135'),
    'title': 'Blacksmith Scene',
    'fullplot': 'A stationary camera looks at a large anvil with a blacksmith behind it and one on either side.',
    'cast': ['Charles Kayser', 'John Ott'],
    'countries': ['USA'],
    'directors': ['William K.L. Dickson'],
    'genres': ['Short'],
    'imdb': {'id': 5, 'rating': 6.2, 'votes': 1189},
    'released': datetime.datetime(1893, 5, 9, 0, 0),
    'runtime': 1,
    'year': 1893
  }

For further reading, see the original article at MongoDB Developer Blog .