Laravel Eloquent ignore attribute if not in table during insert

Question

I have a model Foo that corresponds to a table with the following columns.

id
description
user_id

I'm setting the attributes of the Foo model individually (no mass assignment)

$foo = new Foo;  $foo->id = 1; $foo->description = "hello kitty"; $foo->user_id = 55;  //... 

$foo is sent to another class for additional processing, but because that class needs a bit more information, I would like to simply add it to the $foo model.

//... $foo->bar = $additional_information;  Event::fire(DoStuffWithFoo($foo));  $foo->save();  //error 

the problem is when I $foo->save(), it complains that bar isn't a column.

I know I can unset($foo->bar); before saving, but...

Is it possible to tell Eloquent to simply ignore any non relevant attributes?

Answer 1

Just add $bar as an attribute in your foo class:

class Foo extends Model {    public $bar;   //... 

now you can use save() and Laravel will not try to store bar in the DB.

---

Explanation:

If you call save() on a model, only those attributes that are in the array $model->attributes will be saved to the database. If you define $bar as an attribute in the class Foo, then $foo->bar ="xyz" will never end up in the array $model->attributes.

However, if you do not have declared such an attribute for Foo, then __set() is called because you try to save something in an inaccessible property.

You may check out Laravel\Illuminate\Database\Eloquent\Model.php:

/**      * Dynamically set attributes on the model.      *      * @param  string  $key      * @param  mixed  $value      * @return void      */     public function __set($key, $value)     {         $this->setAttribute($key, $value);     } 

which basically calls

$this->attributes[$key] = $value; 

from Laravel\Illuminate\Database\Eloquent\Concerns\HasAttributes.php.

Now $foo->bar ="xyz" will end up beeing in $foo->attribute['bar'] and this is why save() crashes with ..this column does not exists...

Answer 2

I understand this question is old but it was in top results for a recent search where I was trying to solve a similar problem and I think that this may be an ideal case for Laravel accessors/mutators. I have tested this on Laravel 5.6 but believe it may work as far back as 4.2.

By creating a mutator and accessor rather than a public property it will allow adding the field to fillable for mass assignment while still excluding it from the internal attributes (thus preventing it from errantly saving to the DB). I understand the original request excluded mass-assignment but that doesn't necessarily exclude this answer. I think an example will help:

class Foo extends Model {     //Allow bar in mass assignment     protected $fillable = [             "bar"         ];      /**      * Store bar in protected variable instead of attributes      * Because bar is not set in attributes, Laravel will not try to save it to database      */     protected $bar;      /**      * Mutator method to set bar's value      */     public function setBarAttribute($value)     {         $this->bar = $value;     }      /**      * Accessor method to retrieve bar's value      */      public function getBarAttribute()     {         return $this->bar;     } } 

When this model is created using mass-assignment the mutator (setBarAttribute) method will be called for bar if it exists in the mass-assigned values. Anytime the bar property is accessed the respective get/set method will be called. Because the mutator does not set the value of bar in the model's internal attributes variable the model will not save bar to the database.