laravel-5.3 - Laravel迁移错误

Question

我似乎无法弄清楚为什么我在此迁移文件上收到此错误？

错误

[37;41m [Symfony\Component\Debug\Exception\FatalThrowableError] ←[39;49m ←[37;41m Call to a member function nullable() on null ←[39;49m

文件上的日期是在Customer表中创建外部ID之后的日期。这是laravel 5.3。如何解决此错误？

public function up()
{
    Schema::create('invoices', function (Blueprint $table) {
        $table->increments('id');
        $table->timestamps();           
        $table->integer('customer_id')->unsigned();
        $table->timestamps('date_from')->nullable();
        $table->timestamps('date_to')->nullable();
        $table->date('invoice_date')->nullable();
        $table->date('due_at')->nullable();     
        $table->integer('total_charge')->nullable();
        $table->integer('rate')->nullable();
        $table->integer('total_hours')->nullable();
        $table->string('status')->nullable();
        $table->string('description', 255)->nullable();
        $table->string('notes', 255)->nullable();
        $table->string('invoice_ref')->nullable();  

        $table->foreign('customer_id')
              ->references('id')->on('customers')
              ->onDelete('cascade');                      
    });
}

Answer 1

在这两行中使用timestamp方法...

$table->timestamp('date_from')->nullable();
$table->timestamp('date_to')->nullable();

timestamps()不接受任何参数，并创建两个列: created_at和 updated_at参见 Here