How do you implement data validation in MongoDB?

Short answer: Data validation in MongoDB can be implemented using JSON Schema or custom validation rules to ensure data consistency. Example (using JSON Schema): db.createCollection("products", { validator: { $jsonSchema: { bsonType: "object", required: ["product_name", "price"], properties: { product_name: { bsonType: "string" }, price: { bsonType: "double", minimum: 0 } }

Example code

}
} });

Real-world example (ShopNest)

ShopNest’s SQL Server database stores customers, products, and orders. Good indexes and clear foreign keys keep checkout queries fast and safe.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.