node.js - Unique documents using multiple values in Mongoose Schema

Question

I have a special case where our collection needs to make sure each document is unique based on a combination of the email address, and the sweepstakes_id. I've looked all over, but I can't find how to accomplish this type of validation.

Schema definition:

var submissionSchema = new Schema({
    client_id: {
        type: Schema.Types.ObjectId,
        ref: 'Client',
        index: true
    },
    sweepstakes_id: {
        type: Schema.Types.ObjectId,
        ref: 'Sweepstakes',
        index: true
    },
    email: {
        type: String,
        index: true
   },
   data: {
        type: Schema.Types.Mixed,
        default: []
   }
});

Answer 1

You can enforce that using a unique index that includes both fields:

submissionSchema.index({ email: 1, sweepstakes_id: 1 }, { unique: true });