Mongodb - Add Schema for existing collection

Question

I have a collection in my MongoDB with 13 million of records. Unfortanelly, when I created this collection, no schema was created for it. I would like to know if there is any method that I could add an JSON schema beyond backup the entire the database, create the schema and upload all the data.

Answer 1

You can apply a JSON schema to an existing collection using the collMod command to add a new JSON schema to the collection https://docs.mongodb.com/manual/core/schema-validation/. An example below. However it will only apply to new write operations it will not run against existing documents in the collection.

db.runCommand( {
   collMod: "contacts",
   validator: { $jsonSchema: {
      bsonType: "object",
      required: [ "phone", "name" ],
      properties: {
         phone: {
            bsonType: "string",
            description: "must be a string and is required"
         },
         name: {
            bsonType: "string",
            description: "must be a string and is required"
         }
      }
   } },
   validationLevel: "moderate"
} )