Insert additional data in joining table - mysql

Question

I'm building an application with express and i'm using bookshelf (mysql) js as ORM.
I have a relation many-to-many and i'm trying to store in the joining table some additional data.
My models:
const Product = Bookshelf.Model.extend({
tableName: 'products',
factors() {
return this.belongsToMany('Factor', 'product_factors', 'product_id', 'factor_id')
}
})
const Factor = Bookshelf.Model.extend({
tableName: 'factors',
products() {
return this.belongsToMany('Product')
}
})
Creating new product with relations in 'product_factors' table.
/** Create product */
router.route('/').post((req, res) => {
new Product({name: req.body.name})
.save()
.then(product => {
// attaching relation
product.factors().attach([3, 5])
.then(hz => {
res.status(201).json({
message: 'Product created'
})
})
})
})
The 'product_factors' table
|ID|product_id|factor_id|quantity|
|--|----------|---------|--------|
|1 |10 |3 |NULL |
|2 |10 |5 |NULL |
How can i insert quantity at the same time with attaching relations?

Answer 1

The documentation has an example of how to do that in the model.belongsToMany() section. For convenience here it is:
let Doctor = bookshelf.Model.extend({
patients: function() {
return this.belongsToMany(Patient).through(Appointment);
}
});
let Appointment = bookshelf.Model.extend({
patient: function() {
return this.belongsTo(Patient);
},
doctor: function() {
return this.belongsTo(Doctor);
}
});
let Patient = bookshelf.Model.extend({
doctors: function() {
return this.belongsToMany(Doctor).through(Appointment);
}
});
As you can see in the Doctor and Patient models you must use the .belongsToMany(Model).through(AnotherModel). Then it's just a matter of using the attach(), detach(), updatePivot() and withPivot() methods as needed to handle the data.
Also, since you're defining the joining model you can also use it directly to access and modify the data that related table contains. For example:
Appointment.forge({patient_id: 2, doctor_id: 1, confirmed: true}).save()
or
Appointment.forge({id: 4}).destroy()