如何与多个表建立 Laravel eloquent 关系？

Question

I am trying to make 3 tables relationship like this,

users
    id
    name
roles
    id
    name
companies
    id
    name
company_role_user
    user_id
    role_id
    company_id

Relationships in User.php model

public function companies() {
    return $this->belongsToMany(Company::class, 'company_role_user', 'user_id', 'company_id');
}

public function roles() {
    return $this->belongsToMany(Role::class, 'company_role_user', 'user_id', 'role_id');
}

public function role() {
    // relationship to get role of specific company
}

Relationships in Company.php model

public function users() {
    return $this->belongsToMany(User::class, 'company_role_user', 'company_id', 'user_id');
}

public function roles() {
    return $this->belongsToMany(Role::class, 'company_role_user', 'company_id', 'role_id');
}

public function role() {
    // relationship to get role of specific user
}

I want to get user role for specific company like this

User::find(1)->companies[0]->role->name 

or

Company::find(1)->users[0]->role->name

Answer 1

If you have users

users
– id
– name

and you want them to have many to many relation with companies, you should do:

companies
– id
– name

user_companies
– user_id
– company_id

And for your roles, (many to many) you can do the same:

roles
 - id
 - name

user_roles
 - user_id
 - role_id

You are trying to make many to many 3 tables, when you should be doing it with 2 tables.
Even if you manage, it would be very complicated and confusing.
You should consider which tables should be related to roles, companies should have roles, or users should have roles, you dont need them both to have roles

Answer 2

Your schema looks correct but your model definitions/relations can use a junction/pivot model CompanyRoleUser which will relate these 3 relations as many-to-one/belongsTo and one-to-many/hasMany from Company/Role/User.

class Company extends Model
{
    public function companyRoleUser()
    {
        return $this->hasMany(CompanyRoleUser::class, 'id', 'company_id');
    }
}

class Role extends Model
{
    public function companyRoleUser()
    {
        return $this->hasMany(CompanyRoleUser::class, 'id', 'role_id');
    }
}

class User extends Model
{
    public function companyRoleUser()
    {
        return $this->hasMany(CompanyRoleUser::class, 'id', 'user_id');
    }
}

class CompanyRoleUser extends Model
{
    public function company()
    {
        return $this->belongsTo(Discipline::class, 'id', 'company_id');
    }
    public function role()
    {
        return $this->belongsTo(Speciality::class, 'id', 'role_id');
    }
    public function user()
    {
        return $this->belongsTo(User::class ,'id','user_id');
    }
}

Now you can apply different type of filters for your data like

Fetch users for company A id = 1 with admin role id = 2

User::whereHas('companyRoleUser.company', function ($query) use ($company_id) {
       $query->where('id', $company_id);
     })->whereHas('companyRoleUser.role', function ($query) use ($role_id) {
       $query->where('id', $role_id);
     });
 

Or

User::whereHas('companyRoleUser', function ($query) use ($company_id) {
       $query->where('company_id', $company_id)
             ->where('role_id', $role_id);
     });

Fetch companies with $user_id and $role_id

Company::whereHas('companyRoleUser', function ($query) use ($user_id) {
       $query->where('user_id', $user_id)
             ->where('role_id', $role_id);
     });