外键插入失败

Question

我有两个表，students和parent，我创建了一个指向student表的外键，该表引用了父ID，但是当我插入数据时，数据库的外ID列为空

//Mock function
 var mockPromise = new Promise((resolve, reject) => {
    resolve(<mock response similar to actual promise response>);
});
functionName = jest.fn().mockReturnValueOnce(mockPromise)

//Mock action
const actions = [];
const dispatchAction = jest.fn((dispatchCall) => {
      actions.push(dispatchCall);
});

functionName()(dispatchAction);
expect(dispatchAction).toBeCalledTimes(1)

Schema::create('students', function (Blueprint $table) {
    $table->bigIncrements('id');
    $table->bigInteger('pregistration_id')->unsigned();
    $table->integer('admission_no')->unique();
    $table->string('fname');
    $table->string('mname');
    $table->string('lname');
    $table->date('dob');
    $table->string('primary_school');
    $table->string('form_enrolled');
    $table->string('transfered_from');
    $table->string('transfered_to');
    $table->foreign('pregistration_id')->references('id')
        ->on('pregistrations');
    $table->timestamps();

我的控制器

Schema::create('pregistrations', function (Blueprint $table) {
    $table->engine = 'InnoDB';
    $table->bigIncrements('id')->unsigned();
    $table->string('fname');
    $table->string('mname');
    $table->string('lname');
    $table->string('residence');
    $table->integer('phone');
    $table->string('occupation');
    $table->timestamps();

组件

return Student::create([
    'pregistration_id'=>$request['pregistration_id'],
    'admission_no'=>$request['admission_no'],
    'fname'=>$request['fname'],
    'mname'=>$request['mname'],
    'lname'=>$request['lname'],
    'dob'=>$request['dob'],
    'primary_school'=>$request['primary_school'],
    'form_enrolled'=>$request['form_enrolled'],
    'transfered_from'=>$request['transfered_from'],
    'transfered_to'=>$request['transfered_to'],

请任何可以帮助我的人

下面是我的组件代码

<tr v-for="student in students" :key="student.id">
    <div v-for="pregistration in pregistrations" 
        :key="pregistration.id"></div>
    <td>{{student.id}}</td>
    <td>{{student.admission_no}}</td>
    <td>{{student.fname|upText}}</td>
    <td>{{student.mname|upText}}</td>
    <td>{{student.lname|upText}}</td>
    <td>{{student.dob}}</td>
    <td>{{student.primary_school|upText}}</td>
    <td>{{student.form_enrolled|upText}}</td>
    <td>{{student.transfered_from|upText}}</td>
    <td>{{student.transfered_to|upText}}</td>