laravel中是否存在belongsTo关系的位置？

Question

Example

Role -> hasMany -> User

If I want to get all users with a specific role I would normally do something like this:

$role = Role::findOrFail(1);
User::where('role.id', $role->id)->get()

or

User::where('role_id', $role->id)->get()

My question is: Is there any way to achieve that without using role_id or id. I want to just use the $role object. Something like this would be great:

User::where('role', $role)->get();

I know I can use $role->users, but I leaving this out, because I cannot use that if I have multiple belongsTo relations that I want to query.

Example

$model->where('otherModel', $otherModel1)->where('differentModel', $differentModel1)->get();

Background

A solution like this would help a lot, if you want to rename a primary or a foreign key or if your application has keys with counterintuitive names.

Answer 1

User::where('role', $role)->get();

You can't do this or achieve this directly. That is because you are comparing a column (role) to a hole object. What you could do is define Local Scopes.

I know I can use $role->users, but I leaving this out, because I cannot use that if I have multiple belongsTo relations that I want to query.

Actually, in this case you are not making use of a belongsTo() relationship but a hasMany() one (the opposite). Again, you could create Local Scopes in order to keep constraining your query to get the users that match your conditions.

An example using a custom column/value search as you suggested in the last part of your question:

/** User.php */

public function hasRoleScope($query, $column, $value)
{
    return $query->where("role.{$column}", '=', $value);
}

Then you could do:

/** AnyController.php */

User::has_role('name', 'admin')->get();
// equivalent to: User::where('role.name', '=', 'admin)->get();

You could keep define another one:

/** User.php */

public function scopeActive($query, $value)
{
    return $query->where('active', $value);
}

Then you could do:

/** AnyController.php */

User::active(true)->get();
// equivalent to: User::where('active', true)->get();

The interesting part? You can combine the scopes:

/** AnyController.php */

User
    ::active(false)
    ->has_role('id', 23)
    ->get();