Mongoose: How to avoid inserting duplicate records?

Question

I have written the following mongoose function to create new document in mongodb

createdata: (body) => {
    let sEntry = new SData(Object.assign({}, {
        dataId: body.DataId
    }));
    return sEntry.save();
}

I want to modify the above logic so that it doesn't insert two rows with same dataId

In other words, if a particular value of dataId is already existing in mongo then it should not create another entry with same dataId

Answer 1

You need to first install this mongoose-unique-validator for that. Then after you can define unique: true in

In the second step, you need to define the unique: true in your schema. and also you have to handle the error response.

var SData = mongoose.Schema({
    dataId: { type: String, index: true, unique: true, required: true },
});

createdata: (body) => {
    let sEntry = new SData(Object.assign({}, {
        dataId: body.DataId
    }));
    return sEntry.save(function() {
        console.log(error)
    });
}