I’m pretty new to laravel. Just practicing by trying to rewrite my project management tool but i can’t seem to wrap my head around the hasManyThrough relationship (if it’s even the right one).

Basis

I want every logged in user to have (manage) multiple projects and also every customer to have (commission) multiple projects.

Current structure:

user
Database

• id
• …

Model

    public function projects(){
        return $this->hasMany(Project::class);
    }

customer
Database

• id
• …

Model

    public function projects(){
        return $this->hasMany(Project::class);
    }

project
Database

• id
• …
• manager_id (foreign,references user.id)
• customer_id (foreign, references customer.id)

Model

    public function manager(){
        return $this->belongsTo(User::class);
    }

    public function customer(){
        return $this->belongsTo(Customer::class);
    }

Goal

I want to list my Users customers on the Dashboard. So every unique customer that commissioned a project, that the user is managing. I don’t want to assign a customer directly to a user, because every project should have a manager, not the customer itself.

Tries

I did try to add the following to the User Model:

    public function customers(){
        return $this->hasManyThrough(Customer::class, Project::class);
    }

but i get a error, saying that there is no project_id in the customer table, which of course there isn’t.

Thank you in advance

>Solution :

Since laravel can’t guess that users == managers you have to define the key relationships yourself. Try this:

return $this->hasManyThrough(Customer::class, Project::class, 'manager_id', 'id', 'id', 'customer_id');

https://laravel.com/docs/9.x/eloquent-relationships#has-many-through-key-conventions