如何继承猫鼬模型并将其存储在其他集合中

Question

I need to create a model (NEW) which is almost identical to an existing one (ORIGINAL). The NEW model will have a new field ("expiresAt") that I want to use for MongoDB Time To Live (TTL) feature. For design purposes I don't want to store the NEW model in the same collection as ORIGINAL (only NEW model should have TTL feature).

Example:

//ORIGINAL schema

var OriginalSchema = new Schema({

    id: { type: Schema.Types.ObjectId },
    name: { type: String },
    description: { type:String },
});


//NEW schema

var NewSchema = new Schema({

    id: { type: Schema.Types.ObjectId },
    name: { type: String },
    description: { type:String },
    expiresAt: { 
        type: Date, 
        default: Date.now,
        expires: 24*60*60
    }
});

How can be this achieve by using inheritance?

Answer 1

Mongoose discriminators is a schema inheritance mechanism. They enable you to have multiple models with overlapping schemas on top of the same underlying MongoDB collection. Some details were talked in this link .

var OriginalSchema = new Schema({
    id: { type: Schema.Types.ObjectId },
    name: { type: String },
    description: { type:String },
});

var NewSchema = new Schema({
    expiresAt: { 
        type: Date, 
        default: Date.now,
        expires: 24*60*60
    }
});

var Original = mongoose.model('Original', OriginalSchema);
var NewSch = Original.discriminator('NewSch', NewSchema);