使用 Eloquent 在 Laravel 中链接多个表

Question

I have 3 tables user table, countries table, personal_details table. The structure is as follows

Users:

Schema::create('users', function (Blueprint $table) {
    $table->bigIncrements('id');
    $table->string('role');
    $table->string('email')->unique();
    $table->integer('terms');
    $table->timestamp('email_verified_at')->nullable();
    $table->string('password');
    $table->rememberToken();
    $table->timestamps();
});

Countries:

Schema::create('countries', function (Blueprint $table) {
    $table->bigIncrements('id');
    $table->string('countrycode');
    $table->string('countryname');
    $table->string('code');
    $table->string('flag');
    $table->timestamps();
});

Personal Details:

Schema::create('personal_details', function (Blueprint $table) {
    $table->bigIncrements('id');
    $table->integer('user_id');
    $table->string('first_name');
    $table->string('last_name');
    $table->string('sex');
    $table->date('date_of_birth');
    $table->string('country');
    $table->string('freelancer_type');
    $table->text('about_me');
    $table->timestamps();
});

On the welcome page i need to display users profiles including country and associated flag. here is the code im using

Route

Route::get('/', function () {
    $category = \App\Category::all();
    $user = \App\User::all()->where('role', '==', 'Freelancer');
    $post = \App\Post::paginate(3);
    return view('welcome', compact('category', 'user', 'post'));
});

and the View

@foreach($user as $users)
<div class="col-lg-3 md-6 xs-6" style="text-align: center">
    <div class="card-deck">
        <div class="card shadow p-3 mb-5 bg-white rounded">
            <div class="card-body">
                <img src="/profile_images/{{$users->profileimage->image}}"
                     style="width: 100px; height: 100px; border-radius: 50%">
                <p><span style="font-weight: 900; color: #009dba">{{$users->personaldetails->first_name}} {{$users->personaldetails->last_name}}</span>
                    <br/>
                    <span style="font-size: 11px">
                          {{$users->expertise->profession}}</span>
                </p>
                <p style="font-size: 11px">{{$users->personaldetails->country}},
                    ZAR{{$users->expertise->hourly_rate}}/hr</p>
                <hr>
                <p style="font-size: 11px">{{str_limit($users->personaldetails->about_me, $limit = 80, $end =
                    '...')}}</p>
                {{$users->personaldetails->country->flag}}
                <div style="padding-top: 10px"></div>
                <a href="/users/{{$users->id}}">
                    <button>View Profile</button>
                </a>
            </div>
        </div>
    </div>
</div>
@endforeach

I am receiving the error Trying to get property 'flag' of non-object. Please help

Answer 1

In this line {{$users->personaldetails->country->flag}} you are calling for relational data. Your relational data is working in chain. First $user is calling relation of personal_details table. In the personal_details table you have stored user_id so the relationship is working. But when you are chaining countries table using personaldetails there will be no result as no relationship exists. You can see that your countries table holds information of only about country, no id of personal_details is stored as foreign key in your countries table. If you want to retrieve data through relations you must store id of personal_details table as foreign key in countries table. So if you store personal_detail_id in your country table, there should be no problem.

Your countries table should look like the following:

Schema::create('countries', function (Blueprint $table) {
        $table->bigIncrements('id');
        $table->unsignedBigInteger('personal_detail_id');
        $table->string('countrycode');
        $table->string('countryname');
        $table->string('code');
        $table->string('flag');
        $table->timestamps();
    });