Question

我已经搜索了一段时间，无法找到解决此问题的方法。我在todo_items表中有一个自引用外键

    Schema::create('todo_items', function(Blueprint $table)
            {
                //....
                $table->integer('todo_list_id')->unsigned();
                //Added default(null) to see if it would help
                $table->integer('parent_id')->unsigned()->nullable()->default(null);
                //......
            });

    Schema::table('todo_items',function($table)
           {
               $table->foreign('parent_id')
                ->references('id')
                ->on('todo_items')
                ->onDelete('cascade')
                ->onUpdate('cascade');
           }

还有一个mutator

public function setParentIdAttribute($value){
        $this->attributes['parent_id'] = $value ?: null;
    }

但是，当我尝试使用null parent_id在db中存储TodoItem模型时，它会给我这个错误

SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails ('todo_manager'.'todo_items', CONSTRAINT 'todo_items_parent_id_foreign' FOREIGN KEY ('parent_id') REFERENCES 'todo_items' ('id') ON DELETE CASCADE ON UPDATE CASCADE) (SQL: insert into 'todo_items' ('content', 'parent_id', 'todo_list_id', 'updated_at', 'created_at') values (sadsdasd, null, 1, 2015-05-13 11:38:50, 2015-05-13 11:38:50))

控制器存储方法

public function store(TodoList $list,CreateTodoItemRequest $request)
    {
        $item = new TodoItem($request->all());
        $list->items()->save($item);
        //never reaches here
        dd($item);
        return redirect()->route('lists.show',[$list]);
    }

想知道如何解决这个问题

Answer 1

找出问题所在。显然null被存储为一个字符串（不完全确定为什么如果有人可以提供帮助）但改变了mutator并且它有点hacky ......但它现在有效

public function setParentIdAttribute($value){
        $this->attributes['parent_id'] = $value == "null" ? null : $value;
}

Laravel 5 Null外键错误

控制器存储方法

1 个答案: