Laravel通过复选框更新多对多关联数据及编辑时关联同步方案咨询

实现步骤 #

1. 修正edit方法传参 #

你原有edit方法中选中值取的是首条图书的关联数据，不符合编辑当前图书的需求，需改为取当前编辑$book的对应值，同时多对多关联要取出所有已关联的仓库ID组成数组：

public function edit(Book $book)
{
    $authors = Author::all();
    $selectedAuthor = $book->author_id;

    $publishers = Publisher::all();
    $selectedPublisher = $book->publisher_id;

    $warehouses = Warehouse::all();
    // 取出当前图书已关联的所有仓库ID数组
    $selectedWarehouses = $book->warehouses->pluck('id')->toArray();

    return view('books.edit', compact(
        'book', 'authors', 'publishers', 'warehouses',
        'selectedAuthor', 'selectedPublisher', 'selectedWarehouses'
    ));
}

2. 修改视图复选框代码 #

新增默认选中判断，使用Laravel内置的@checked指令实现已关联仓库默认勾选：

@foreach($warehouses as $warehouse)
    <input type="checkbox" name="checked[]" value="{{ $warehouse->id }}" 
        @checked(in_array($warehouse->id, $selectedWarehouses))
    >
    {{ $warehouse->address }}
    <br/>
@endforeach

3. 完善update方法的关联同步逻辑 #

直接使用Laravel多对多关联提供的sync方法即可，它会自动完成「删除取消勾选的关联、新增新勾选的关联」的逻辑，不需要手动编写attach/detach代码：

public function update(Request $request, Book $book)
{
    $request->validate([
        'ISBN' => 'required',
        'publisher_id' => 'required',
        'author_id' => 'required',
        'year' => 'required',
        'title' => 'required',
        'price' => 'required',
    ]);

    try {
        $book->update($request->all());

        // 同步仓库关联，空数组默认值用于处理用户全不勾选的场景
        $book->warehouses()->sync($request->checked ?? []);

        return redirect()->route('books.index')
            ->with('success','Book updated successfully.');

    } catch (\Illuminate\Database\QueryException $e) {
        var_dump($e->errorInfo);
    }
}

额外优化建议 #

你原有store方法中的循环attach逻辑也可以替换为sync方法，代码更简洁：

// 替换原有foreach循环
$book->warehouses()->sync($request->checked ?? []);

内容的提问来源于stack exchange，提问作者Xelerate