Questions related to soft delete in laravel

Question

I have some questions relating to soft delete in laravel. I have search up on what it does and what it means and the most understandable part about soft delete is from this sentence

"When models are soft deleted, they are not actually removed from your database. Instead, a deleted_at attribute is set on the model and inserted into the database. If a model has a non-null deleted_at value, the model has been soft deleted. To enable soft deletes for a model, use the Illuminate\Database\Eloquent\SoftDeletes trait on the model and add the deleted_at column to your $dates property:"

So here are my questions based from that sentence:

Q1:

So when I use soft delete in my code, and when I try to delete some data, does the data in the view page(blade.php) disappear while the database still contain those data?

Q2:

I saw some people using something called static::deleting, I don't really quite get how this work? Could you explain what it does? Thank you

Q3:

How do you delete data using soft delete? I saw people just putting some stuff into their model instead of using button, so does that mean you can only delete it manually inside the model instead of just clicking the delete button in the view page?

Answer 1

Question 1

By default: Yes.
It depends on your query. When using soft deletes, Laravel will query all models that are not soft-deleted by default. When you also want to get the soft-deleted models, you need to call the withTrashed() method on your query. Read more here:
https://laravel.com/docs/5.5/eloquent#querying-soft-deleted-models

To understand what withTrashed() does, you need to understand how soft-deleting works. Soft-deleting models works by adding a new column to your database tables called deleted_at. It's value defaults to null. When you soft-delete a model, Laravel will put the current timestamp into that column. Therefore, this field doesn't contain a null value anymore.

When querying models when using soft-deletes, Laravel appends a deleted_at is null condition to the query. Calling the withTrashed() method, removes that condition from the query.

Have a look on the source of the default query modifier and the withTrashed method.

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Question 2

That are events. You can call that to tell Laravel, that it should execute that specific closure when this event happens. In your example, it is listening for the "deleting" event. See more on that here:
https://laravel.com/docs/5.5/eloquent#events

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Question 3

You can entirely delete soft-deletable models with the forceDelete() method. See "Permanently Deleting Models" here:
https://laravel.com/docs/5.5/eloquent#querying-soft-deleted-models

Answer 2

Q1: So when I use soft delete in my code, and when I try to delete some data, does the data in the view page(blade.php) disappear while the database still contain those data?

Yes. The soft delete fill the deleted_at column in the database. Since that, Eloquent will not retrieve these data (except if you ask for). If you use custom SQL request, you'll need to add a WHERE deleted_at IS NULL

Q2: I saw some people using something called static::deleting, I don't really quite get how this work? Could you explain what it does? Thank you

I'm not using that day to day, but it's an event you can call (see here ) to automatically delete content related (for example, if you remove an user, you can also remove all his post. It's kind of cascading delete)

Q3: How do you delete data using soft delete? I saw people just putting some stuff into their model instead of using button, so does that mean you can only delete it manually inside the model instead of just clicking the delete button in the view page?

To use the soft delete, you just $object->detroy($id) or $myEloquentRequest->where(...)->delete() If you want to force a real delete (so the entries will be definitly removed from the database), you can use $flight->forceDelete(); See here for more. You can do the delete wherever you want. The click on a button bring the user to the delete() method in your controller. You can delete there or call a method inside the model to trigger the delete (and maybe some more complex deleting like event ... )

Answer 3

Soft delete means not delete records in database.So we handle one flag for manage records is deleted or not.

Let's i explain more with examples :

In our records many user so we add one fields delete_at into database and defaults it's value null so it's records is not deleted.

Now when we fetch all user data we write query like

Select * from user where delete_at = null

So this query return all user data which is not deleted.

Now we delete this user so when we click on delete button we create custom query and update this user delete_at fields with current datetime

Update delete_at=date() where user_id = 1

so now this records is soft delete.

Now i answer your question:

Q.1)No data not displaying after soft delete because when we fetch data it's check delete_at fields null or not.

Answer 4

clarifying your points. 1. So when we use soft delete in code, deleted_at will be updated to present timestamp from null, so while querying data from that particular table from anywhere in your project the eloquent model will automatically return data whose deleted_at is set NULL i.e., it is not soft deleted.

2. people using something called static::deleting. you might have seen somewhat like this example if I am understanding your question in right way:

   class X-Model extends Eloquent {

   public function xy()
   {
       return $this->has_many('XY_Model');
   }
   
   // this is a recommended way to declare event handlers
   protected static function boot() {
       parent::boot();
   
       static::deleting(function($x) { 
        // before delete() method call this
            $user->xy()->delete();
            // do the rest of the cleanup...
       });
   }
   

   } This is a use-case for Eloquent events to delete a record which will use the "deleting" event to do the cleanup.

3. delete data using soft delete

now after calling this, you can soft delete the data from the table and also u can soft delete the data from other dependent tables if relationships are maintained properly in models. this is actually known as cascading effect. example for you to understand. Model structure:

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use App\Utilities\Uuids;
use Illuminate\Database\Eloquent\SoftDeletes;
use Iatstuti\Database\Support\CascadeSoftDeletes;

class XFolder extends Model
{
    use SoftDeletes, CascadeSoftDeletes;
    use Uuids;
    protected $connection = 'XDB';
    protected $table = 'x_folder';
    protected $dates = ['deleted_at'];
    public $incrementing = false;
    protected $cascadeDeletes = ['XReference']; //related table with foreign keys
    protected $visible = [ 'id', 'x_id', 'xz_id', 'at_id', 'title', 'description', 'description', 'status', 'created_on' , 'is_active'];

    protected $fillable = [
     'x_id',
     'xz_id',
     'at_id',
     'title',
     'description',
     'status',
     'created_on',
     'is_active'
    ];

    public function XReference()
    {
        return $this->hasMany('App\Models\XReference', 'x_id');
    }
}

now in the controller you can call like this:

public function deleteData($id)
    {
        $results = $this->getModel()->where('id', $id)->deleteData();
        return $results;
    }

this will delete data (soft delete in cascading format).

Answer 5

Q1: So when I use soft delete in my code, and when I try to delete some data, does the data in the view page(blade.php) disappear while the database still contain those data?

Yes, if your model use softDelete, than the search query will be like this: Select * from table_name where delete_at = null

Q2: I saw some people using something called static::deleting, I don't really quite get how this work? Could you explain what it does?

You can do it with: Modelname::destroy($id) static action

It destroys the model object where the $id is set. On destroying I mean: it updates the deleted_at column, so the aplication will see it as a soft deleted object

Q3: How do you delete data using soft delete? I saw people just putting some stuff into their model instead of using button, so does that mean you can only delete it manually inside the model instead of just clicking the delete button in the view page?

Example of one of my project:

I have a delete button at the partner screen what routes to partner/{{ id }}/delete

at the routes: Route::get('/partner/{id}/delete', 'PartnerController@deletePartner');

What goes to this action:

public function deletePartner($partnerId = 0){

    if ($partnerId > 0){
        Partner::destroy($partnerId);
    }

    return redirect("/partner");
}

So: If I click to delete button it check, that the ID is set and then "destroys it" (soft delete). After deletion it redirects back to the partner

EDIT:

For the example given in the question 3, when you delete the data, does the database data disappear or only the view?

It will dissapear only from the view. In the database it will be stored as:

id name ... created_at       updated_at       deleted_at
1  foo  ... 2017-10-01 00:00 2017-10-01 00:00 NULL
2  bar  ... 2017-10-01 00:00 2017-10-01 00:00 2017-10-25 16:00

The first one is a non-deleted the second one is a soft-deleted object and the view only will show the first one