Does MongoDB support primary-key, foreign-key relationship?

MongoDB, as a NoSQL database, does not support traditional primary-key and foreign-key relationships like those found in relational databases. In MongoDB, data is stored in flexible, JSON-like documents in BSON (Binary JSON) format. Each document can have its own structure, and there is no need for a predefined schema.

Instead of using primary keys and foreign keys to establish relationships between documents, MongoDB uses the concept of references or embedded documents to represent relationships:

1. References: You can manually store references to documents in one collection within documents in another collection. This is similar to the concept of foreign keys, but it requires manual management of relationships.
2. Embedded Documents: You can embed documents directly within other documents. This is similar to the concept of denormalization, where related data is stored together for better performance.

While MongoDB does not enforce relationships at the database level, it provides powerful querying capabilities and indexing to efficiently retrieve related data. It’s important to design your schema based on the specific requirements of your application and the queries you will be performing.

In summary, MongoDB does not have built-in support for primary-key and foreign-key relationships in the traditional relational database sense, but it provides flexibility in how you model and represent relationships between documents.