Question

我似乎无法弄清楚为什么我在此迁移文件中收到此错误？

错误

[37; 41m [Symfony \ Component \ Debug \ Exception \ FatalThrowableError]←[39; 49m ←[37; 41m在null上调用成员函数nullable（）←[39; 49m

文件上的日期是在Customers表中创建外来ID之后。这是laravel 5.3。我该如何解决这个错误？

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os.listdir('/Users/liuchong/Desktop/LFW/lfw')方法......

def copyFile(sourceDir,targetDir):
    for files in os.listdir(sourceDir):
        sourceFile=os.path.join(sourceDir,files)
        if os.path.isfile(sourceFile) and sourceFile.find('.jpg')>0:
            shutil.copy(sourceFile,targetDir)

for i in os.listdir('/Users/liuchong/Desktop/LFW/lfw'):
     if os.path.isdir(i):
         i = os.path.join( '/Users/liuchong/Desktop/LFW/lfw', i)
         copyFile(i,'/Users/liuchong/Desktop/LFW/lfw')

timestamp不接受任何参数并创建两个列：$table->timestamp('date_from')->nullable(); $table->timestamp('date_to')->nullable();和timestamps() 见Here

Answer 2

从代码中删除这两行

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

仅包含此行以进行timpstamping：

 $table->timestamps();

Laravel迁移错误

2 个答案: