错误：外键约束形成不正确

Question

我的HOOFDVRAAGS数据库中存在外键错误，但奇怪的是这与VRAAGS完全相同

SQLSTATE [HY000]：一般错误：1005无法创建表zonetoets.#sql-1 e8_2f9（错误：150“外键约束形成错误”）（SQL：a lter table hoofdvraags add constraint hoofdvraags_toets_id_foreign fore ign key（toets_id）引用toets（id） ）删除级联）在Connection.php第458行： SQLSTATE [HY000]：常规错误：1005无法创建表zonetoets.#sql-1 e8_2f9（错误号：150“外键约束形成错误”）

在此我的db-migrations，希望有人可以帮助我。因此关系TOETS 1 ----> N HOOFDVRAAGS 1 ----> N VRAAGS

主要问题

<?php

use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class CreateHoofdvraagsTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('hoofdvraags', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('toets_id')->unsigned();
            $table->string('titel');
            $table->string('tekst');
            $table->string('bestandsnaam');
            $table->integer('volgnummerHoofdvraag')->default(99);             
            $table->timestamps();

            $table->foreign('toets_id')
                -> references('id')
                -> on('toets')
                -> onDelete('cascade');
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('hoofdvraags');
    }
}

BUTTON

<?php

use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class CreateToetsTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('toets', function (Blueprint $table) {
            $table->increments('id');
            $table->string('toetscode');
            $table->string('jaargang');
            $table->string('vak')->default('wiskunde');
            $table->string('hoofdstuk');
            $table->string('hoofdstuktitel');
            $table->string('maker');
            $table->string('datumgemaakt');   
            $table->integer('volgnummerToets')->default(1);     
            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('toets');
    }
}

问题

<?php

use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class CreateSubvraagsTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('subvraags', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('hoofdvraag_id')->unsigned();
            $table->string('vraag');
            $table->string('antwoord');
            $table->integer('punten');
            $table->string('bestandsnaam');
            $table->integer('volgnummerSubvraag')->default(1);
            $table->timestamps();

            $table->foreign('hoofdvraag_id')
                -> references('id')
                -> on('hoofdvraags')
                -> onDelete('cascade');
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('subvraags');
    }
}

模型键

public function hoofdvraag()
    {
        return $this->hasMany(Hoofdvraag::class);
    }

模型主要问题

public function subvraag()
    {
        return $this->hasMany(Subvraag::class);
    }

    public function toets() {
        return $this->belongsTo(Toets::class);
    }

模型子问题

public function hoofdvraag() {
        return $this->belongsTo(Hoofdvraag::class);
    }

Answer 1

据我所知，如果你在模型中创建一个雄辩的实现，为什么要在迁移中创建外键，只需要为它创建一个列。

https://laravel.com/docs/5.8/eloquent-relationships#one-to-many