How can I load only existing preload data?

[positivedeveloper36]

I have a relation between my category table and my dishes table but when I preload dishes it loads dishes which have empty relation as well

My code like this :

const data = await Category
    .query()
    .preload('dishes',(query) => {
        query.select('id', 'name);
    })
    .paginate(1,2)

I want only those category which have relation with dishes

I try use whereHas like this :

const data = await Category
    .query()
    .whereHas('dishes', () => {})
    .preload('dishes',(query)=>{
    query.where('id',name);
   }).paginate(1,2);

It works. It success show only those category which have relation with dishes

But is that the best way? Because this uses whereHas and preload together

[Barbapapazes]

Hello,

'request.input('user_id') doesn't exist' is a valide use case of your application?

If not, you can try to use a validator to be sure that this input exist!

[positivedeveloper36]

@Barbapapazes You don't seem to understand what I mean. I updated my question. Hope you know what I
mean

[Barbapapazes]

But is that the best way? Because this uses whereHas and preload together

Yes! What do you think is wrong using preload and whereHas? Under the hood, the request is

# If dishes have one categories and categories have many dishies
select * from "categories" where exists (select * from "dishes" where "dishies"."id" = ? and "dishes"."categorie_id" = "categories"."id");
# If there is no related categories, the row is not relected in th subquery so the categorie is no selected in the main query.

And this is a valide query and I can't thing you can do a better job than this. You can manually use a join or a in but here, you're main request is not affected (no new column, only data from the categories table will be fetched).

The preload is not present in this SQL query because it's done along side the main query.

Hope I anwser!

[positivedeveloper36]

@Barbapapazes I use model so I don't use join fo query builder. What do yo mean in?

[positivedeveloper36]

Yes I have checked that. If I debug the query and run it in pgadmin. It looks a bit weird like you said. So to make sure the data match I'm using postman and I think the best way is use whereHas and preload together. Because when I use both and check in postman it displays correct data