laravel Eloquent ORM delete() method

问题

Hi I am studying laravel. I use Eloquent ORM delete method but I get a different result.Not true or false but null. I set an resource route and there is a destroy method in UsersController.

public function destroy($id){

  $res=User::find($id)->delete();
  if ($res){
    $data=[
    'status'=>'1',
    'msg'=>'success'
  ];
  }else{
    $data=[
    'status'=>'0',
    'msg'=>'fail'
  ];
  return response()->json($data);

But I always get a response {"status":"0","msg":"failed"},the record in the database is deleted.

Then I use dd($res) .It shows null in the page.

But from the course I learn it returns a boolean value true or false.

Is there any error in my code?

Can you tell me some other method that I can get a boolean result when I delete data from database?

回答1:

I think you can change your query and try it like :

$res=User::where('id',$id)->delete();

回答2:

At first,

You should know that destroy() is correct method for removing an entity directly via object or model and delete() can only be called in query builder.

In your case, You have not checked if record exists in database or not. Record can only be deleted if exists.

So, You can do it like follows.

$user = User::find($id);
    if($user){
        $destroy = User::destroy(2);
    }

The value or $destroy above will be 0 or 1 on fail or success respectively. So, you can alter the $data array like:

if ($destroy){

    $data=[
        'status'=>'1',
        'msg'=>'success'
    ];

}else{

    $data=[
        'status'=>'0',
        'msg'=>'fail'
    ];

}

Hope, you understand.

回答3:

Laravel Eloquent provides destroy() function in which returns boolean value. So if a record exists on the database and deleted you'll get true otherwise false.

Here's an example using Laravel Tinker shell.

In this case, your code should look like this:

public function destroy($id)
    {
        $res = User::destroy($id);
        if ($res) {
            return response()->json([
                'status' => '1',
                'msg' => 'success'
            ]);
        } else {
            return response()->json([
                'status' => '0',
                'msg' => 'fail'
            ]);
        }
    }

More info about Laravel Eloquent Deleting Models

回答4:

$model=User::where('id',$id)->delete();

回答5:

You can use :

$data = Model::findOrFail($id);
$data->delete();

回答6:

Before delete , there are several methods in laravel.

User::find(1) and User::first() return an instance.

User::where('id',1)->get and User::all() return a collection of instance.

call delete on an model instance will returns true/false

$user=User::find(1);
$user->delete(); //returns true/false

call delete on a collection of instance will returns a number which represents the number of the records had been deleted

//assume you have 10 users, id from 1 to 10;
$result=User::where('id','<',11)->delete(); //returns 11 (the number of the records had been deleted)

//lets call delete again
$result2=User::where('id','<',11)->delete(); //returns 0 (we have already delete the id<11 users, so this time we delete nothing, the result should be the number of the records had been deleted(0)  )

Also there are other delete methods, you can call destroy as a model static method like below

$result=User::destroy(1,2,3);
$result=User::destroy([1,2,3]);
$result=User::destroy(collect([1, 2, 3]));
//these 3 statement do the same thing, delete id =1,2,3 users, returns the number of the records had been deleted

One more thing ,if you are new to laravel ,you can use php artisan tinker to see the result, which is more efficient and then dd($result) , print_r($result);

来源：https://stackoverflow.com/questions/45458074/laravel-eloquent-orm-delete-method

标签

php

laravel

laravel-eloquent