Introduction to Document Validation in MongoDB

Learn how to enforce data consistency and integrity by setting up document validation rules in MongoDB collections.

Prerequisites

Before you begin, make sure you have the following prerequisites:

• An active MongoDB deployment.
• Basic knowledge of MongoDB and its data model.

1. What is Document Validation?

Understand the concept of document validation in MongoDB and why it's important for maintaining data quality.

2. Validation Rules

Learn how to define validation rules for your MongoDB collections. Sample code for creating a validation rule:

// Create a validation rule
db.createCollection("products", {
    validator: {
        $jsonSchema: {
            bsonType: "object",
            required: ["name", "price"],
            properties: {
                name: {
                    bsonType: "string",
                    description: "Name must be a string."
                },
                price: {
                    bsonType: "decimal",
                    description: "Price must be a decimal."
                }
            }
        }
    }
});
        

3. Validation Actions

Explore validation actions, including error messages and the `validationLevel` option. Specify how MongoDB handles documents that violate validation rules.

4. Updating Validation Rules

Learn how to update validation rules for existing collections. Sample code to modify a validation rule:

// Update a validation rule
db.runCommand({
    collMod: "products",
    validator: {
        $jsonSchema: {
            bsonType: "object",
            required: ["name", "price", "description"],
            properties: {
                name: {
                    bsonType: "string",
                    description: "Name must be a string."
                },
                price: {
                    bsonType: "decimal",
                    description: "Price must be a decimal."
                },
                description: {
                    bsonType: "string",
                    description: "Description must be a string."
                }
            }
        }
    }
});
        

5. Conclusion

You've learned how to implement document validation in MongoDB, including defining validation rules, handling validation actions, and updating validation rules. Document validation is a powerful tool for maintaining data quality and consistency in your MongoDB collections.