LaravelEloquent 更新，如果已经作出更改

如果 Laravel 的记录发生了变化，有没有办法用雄辩的模型来更新这一记录呢？我不希望任何用户无缘无故地一遍又一遍地请求数据库，只需要按下按钮来保存更改。我有一个 javascript功能，启用和禁用的保存按钮，根据是否有什么改变在页面，但我想知道是否有可能确保这种功能在服务器端也。我知道我可以通过检查记录是否有变化来自己完成它(意思是: 不需要依赖框架的内部功能) ，但是在这样做之前，我想知道 Laravel 雄辩模型是否已经处理好了这个问题，所以我不需要重新发明轮子。

这是我用来更新记录的方法:

$product = Product::find($data["id"]);
$product->title = $data["title"];
$product->description = $data["description"];
$product->price = $data["price"];
//etc (string values were previously sanitized for xss attacks)
$product->save();
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最佳答案

You're already doing it!

save() will check if something in the model has changed. If it hasn't it won't run a db query.

Here's the relevant part of code in Illuminate\Database\Eloquent\Model@performUpdate:

protected function performUpdate(Builder $query, array $options = [])
{
$dirty = $this->getDirty();


if (count($dirty) > 0)
{
// runs update query
}


return true;
}

The getDirty() method simply compares the current attributes with a copy saved in original when the model is created. This is done in the syncOriginal() method:

public function __construct(array $attributes = array())
{
$this->bootIfNotBooted();


$this->syncOriginal();


$this->fill($attributes);
}


public function syncOriginal()
{
$this->original = $this->attributes;


return $this;
}

If you want to check if the model is dirty just call isDirty():

if($product->isDirty()){
// changes have been made
}

Or if you want to check a certain attribute:

if($product->isDirty('price')){
// price has changed
}
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I like to add this method, if you are using an edit form, you can use this code to save the changes in your update(Request $request, $id) function:

$post = Post::find($id);
$post->fill($request->input())->save();

keep in mind that you have to name your inputs with the same column name. The fill() function will do all the work for you :)

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You can use $product->getChanges() on Eloquent model even after persisting. Check docs here

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At times you need to compare the newly changed value with the previous one and if you are looking for that here is the solution.

if (
$obj->isDirty('some_field_name') &&
$obj->some_field_name != $obj->getOriginal('some_field_name')
) {
// Make required changes...
}
});
}

The reference of the derived solution is here.

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use only this:

Product::where('id', $id)->update($request->except(['_token', '_method']));

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