laravel - SQLSTATE[23000] : Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails Laravel

Question

我有两张表，一张用于用户，一张用于新项目。我在项目表的用户表中引用了 id。

 public function up()
    {
        Schema::create('items', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('user_id')->unsigned();
            $table->string('item_title');
            $table->timestamps();
        });

        Schema::table('items', function($table) {
             $table->foreign('user_id')->references('id')->on('users');
        });

这是我用于添加新项目的 Controller

public function storeItem(Request $request){
        $user = Auth::user();

        $item = new Item([
            'user_id' => $user->id,
            'item_title' => $request->input('title'),
        ]);

        $item->save();    
    }

但是当我提交表单时，出现此错误SQLSTATE[23000]:违反完整性约束:1452 无法添加或更新子行:外键约束失败(database.items, CONSTRAINTitems_user_id_foreign外键 (user_id) 引用users(id))

有什么想法吗？

Answer 1

好吧，首先尝试修复您的迁移:

public function up()
{
    Schema::create('items', function (Blueprint $table) {
        $table->increments('id');
        $table->integer('user_id')->unsigned();
        $table->string('title');
        $table->timestamps();

        $table->foreign('user_id')->references('id')->on('users')->onDelete('restrict');
    });
}

public function down()
{
    Schema::drop('items');
}

运行$ php artisan migrate:refresh

Note: using prefix "item_" is looking bad, you already have table named as item(s), so drop the prefix... name your columns properly

Controller (方法)

public function storeItem(Request $request, App\Item $item) 
{
    $user = $request->user(); // get current user making the request

    $data = array_merge($request->only(['title']), ['user_id' => $user->id]);
    $newItem = $item->create($data);
    //$newItem has instance of your created item
}

Note: remember to correctly fill $fillable array in your Item model (in this case it should have only 'title' and 'user_id')