Can a Schema use it's own model to validate?

Question

Can a Schema use it's own model to validate?

For example, say I have a user schema, and I want to validate that the username is unique before even attempting to save the user to the database.

...

UserSchema.path('username')
  .validate(function (value, respond) {
    User.findOne({ username: this.username }) // This isn't valid.
      .lean()
      .select('_id')
      .exec(function (err, user) {

        if (err) {
          winston.warn('User_username: Error looking for duplicate users');
          respond(false);
        }

        // If a user was returned, then the user is non-unique!
        if (user) {
          respond(false);
        }

        respond(true);
      });
  });

...

var User = mongoose.model('User', UserSchema);

I know I could use mongoose.model('User').findOne(...) but that just seems a bit silly, is there no better way to do it?

node.js
mongoose

Answer 1

You can create an unique index in your schema by setting unique: true. This will make use of the unique index option that is available in mongodb. Here is an example snippet from one of my models using this option:

// The (generated) uniform resource locator
url: {
    // ... which is required ...
    required: true,
    // ... which is an unique index ...
    unique: true,
    // ... and is a string.
    type: String
}

Compound key from comments:

Schema.index({ username: 1, accountCode: 1 }, { unique: true })