Eloquent model not updating updated_at timestamp

Title: Eloquent Model Timestamp Updates in Laravel Body: You're encountering a specific issue where your Eloquent model isn't updating the 'updated_at' timestamp when performing updates, but it does update on insertions as expected. This might be confusing, given that the documentation claims timestamps should be updated automatically upon any database activity involving models. Let's dive into this issue and find a solution. Firstly, ensure that you are using Laravel 5.1, as the issues with timestamps in other versions of Laravel might not apply to your situation. The timestamps() function during migration creates the updated_at and created_at columns and sets them automatically for each model instance. This should work across all database operations involving models. However, you have noticed that only on insertions the timestamp is updated, but not on updates. Let's examine your code. You have a migration file with timestamps enabled:

Schema::create('sitemap_data', function (Blueprint $table) {
    // Primary and foreign keys
    $table->increments('id');
    $table->string('postUrl');
    // Database functions
    $table->timestamps();
});

Your code involves an Eloquent model instance, SitemapData. You first create a new or retrieve an existing record with firstOrNew(), and then save the model with its changes:

$sitemapData = SitemapData::firstOrNew([
                    'postUrl' => $post
                ]);
$sitemapData->save();

When the model is saved, you are manually setting the updated_at timestamp without any issues. Laravel documentation explains that a simple save() method should update the timestamps accordingly. However, your experience shows otherwise. The issue might arise from how timestamps are handled internally. When an Eloquent model instance is created, its 'created_at' and 'updated_at' columns are set to null. The timestamp values will be updated only during the first save() call. After that, Laravel will keep these values as they are until an explicit update is performed on those two columns. To solve this problem, you need to force a new instance of your model each time before saving it. This ensures that your model has default date values for the timestamps and thus gets updated with the actual date when saving:

$sitemapData = SitemapData::findOrNew([
                    'id' => $existingId,
                    'postUrl' => $post
                ]);

// If no record exists with this ID, a new model instance will be created and its timestamps updated.
$sitemapData->updated_at = Carbon::now();
$sitemapData->save();

To recap: Your code was working as intended, but you might have missed the point about when and how timestamps are updated in Eloquent models. When dealing with updates, create a new model instance if necessary to ensure the timestamps are updated according to your expectations. This best practice guarantees that timestamps will be set whenever appropriate while preserving their default values during initial creation.