Create or Update Sequelize

Question

I'm using Sequelize in my Nodejs project and I found a problem that I'm having a hard time to solve. Basically I have a cron that gets an array of objects from a server than inserts it on my database as a object ( for this case, cartoons ). But if I already have one of the objects, I have to update it.

Basically I have a array of objects and a could use the BulkCreate() method. But as the Cron starts again, it doesn't solve it so I was needing some sort of update with an upsert true flag. And the main issue: I must have a callback that fires just once after all these creates or updates. Does anyone have an idea of how can I do that? Iterate over an array of object.. creating or updating it and then getting a single callback after?

Thanks for the attention

Answer 1

From the docs, you don't need to query where to perform the update once you have the object. Also, the use of promise should simplify callbacks:

Implementation

function upsert(values, condition) {
    return Model
        .findOne({ where: condition })
        .then(function(obj) {
            // update
            if(obj)
                return obj.update(values);
            // insert
            return Model.create(values);
        })
}

Usage

upsert({ first_name: 'Taku' }, { id: 1234 }).then(function(result){
    res.status(200).send({success: true});
});

Note

1. This operation is not atomic.
2. Creates 2 network calls.

which means it is advisable to re-think the approach and probably just update values in one network call and either:

1. Look at the value returned (i.e. rows_affected) and decide what to do.
2. Return success if update operation succeeds. This is because whether the resource exists is not within this service's responsibility.