Laravel 5.4外键关系在表中显示null

Question

我试图在我的查询表中保存客户端和设备外键，但不知何故，它一直返回null（我的迁移为空）。我得到没有错误，如果我返回$客户端或$设备它返回一个正确的ID。

这就是控制器的样子：

# foreign key in this table rreturns null InquiryController
public function store(Request $request)
{
    $input = $request->all();

    $client = Client::find($request->input('client_id'));
    $device = Device::find($request->input('device_id'));
    $stream = new Stream;
    $stream->stream_name = $request->input('stream_name');
    $stream->save();

    $inquiry = new Inquiry;
    $inquiry->fill($data);
    $inquiry->client()->associate($client);
    $inquiry->device()->associate($device);
    $inquiry->stream()->associate($stream);
    $inquiry->save();
}

这是我的调查模型

class Inquiry extends Model
{
    protected $table    = 'inquiries';
    protected $fillable = ['user_id', 'client_id', 'device_id', 'stream_id'];

    # relations
    public function user()
    {
        return $this->belongsTo(User::class);
    }
    public function client()
    {
        return $this->belongsTo(Client::class);
    }
    public function device()
    {
        return $this->belongsTo(Device::class);
    }
    public function stream()
    {
        return $this->belongsTo(Stream::class);
    }
}

这是客户端和设备模型的关系函数：

public function inquiry()
{
    return $this->hasMany(Inquiry::class);
}

移民：

public function up()
{
    Schema::create('inquiries', function(Blueprint $table)
    {
        $table->increments('id');
        $table->unsignedInteger('client_id')->nullable();
        $table->unsignedInteger('device_id')->nullable();
        $table->timestamps();
        $table->foreign('client_id')->references('id')->on('clients')->onDelete('cascade');
        $table->foreign('device_id')->references('id')->on('devices')->onDelete('cascade');
    });
}

public function down()
{
    Schema::dropIfExists('inquiries');
}

Answer 1

确保在迁移过程中为查询表定义了外键。

例如：

$table->integer('client_id')->unsigned();
$table->foreign('client_id')
  ->references('id')->on('clients')
  ->onDelete('cascade');

更新：

尝试在添加关系之前保存模型。将其交换到：

$inquiry = new Inquiry;
$inquiry->fill($data);
$inquiry->save();
$inquiry->client()->associate($client);
$inquiry->device()->associate($device);
$inquiry->stream()->associate($stream);