How to check data exists in the database - laravel

Question

I have a function to add new property. But i want to check for duplicate data at column "code" before add new data into database. If data exists will appear a message error.
function addPro(Request $req)
{
$id = $req->type_id;
$type = AssetType::find($id);
if($req->save == 'save'){
$pro = new TypeProperties;
$pro->name = $req->name;
$pro->code = $req->code;
$pro->type = $req->type;
$pro->assettype_id = $req->type_id;
$pro->save();
Schema::table($type->code, function ($table) use ($pro) {
if ($pro->type == "textbox")
$table->string($pro->code )->nullable();
if ($pro->type == "textarea")
$table->text($pro->code )->nullable();
});
return redirect(url($type->id.'/add/property'))->with('message','Save successful');
}
return redirect(url('asset/type/'.$type->id));
}

Answer 1

You can use laravel Request Validation
function addPro(Request $req)
{
$id = $req->type_id;
$type = AssetType::find($id);
if($req->save == 'save'){
$req->validate([
'code' => 'required|unique:tablename'
]);
$pro = new TypeProperties;
$pro->name = $req->name;
$pro->code = $req->code;
$pro->type = $req->type;
$pro->assettype_id = $req->type_id;
$pro->save();
Schema::table($type->code, function ($table) use ($pro) {
if ($pro->type == "textbox")
$table->string($pro->code )->nullable();
if ($pro->type == "textarea")
$table->text($pro->code )->nullable();
});
return redirect(url($type->id.'/add/property'))->with('message','Save successful');
}
return redirect(url('asset/type/'.$type->id));
}

Answer 2

The most simple way to do this is by checking if code is_null :
if (is_null($pro->code)) {
// It does not exist
} else {
// It exists
}
The other way is to make a validation using Laravel's built in ValidateRequest class. The most simple use-case for this validation, is to call it directly in your store() method like this:
$this->validate($req, [
'code' => 'required|unique,
//... and so on
], $this->messages);
With this, you're validating users $req by saying that specified columns are required and that they need to be unique, in order for validation to pass. In your controller, you can also create messages function to display error messages, if the condition isn't met:
private $messages = [
'code.required' => 'Code is required',
'code.unique' => 'Code already exists',
//... and so on
];
You can also achieve this by creating a new custom validation class:
php artisan make:request StorePro
The generated class will be placed in the app/Http/Requests directory. Now, you can add a few validation rules to the rules method:
public function rules()
{
return [
'code' => 'required|unique,
//... and so on
];
}
All you need to do now is type-hint the request on your controller method. The incoming form request is validated before the controller method is called, meaning you do not need to clutter your controller with any validation logic:
public function store(StorePro $req)
{
// The incoming request is valid...
// Retrieve the validated input data...
$validated = $req->validated();
}
If you have any additional question about this, feel free to ask. Source: Laravel official documentation.

Answer 3

What does your migration look like for AssetType?
I ask because you can do this in the schema with ->unique() added to the column on the creation or make a migration to add the constraint.
You can also check with something like this:
// Search database table for entry
$entry = AssetType::where('code', '=', $pro->code)->first();
// If not found
if ($entry === null) {
// Save method here.
}
Otherwise, you can use the manual validator or create a Request with validation
References:
https://laravel.com/docs/5.8/queries#where-clauses
https://laravel.com/docs/5.8/validation#creating-form-requests
https://laravel.com/docs/5.8/validation#manually-creating-validators