diff --git a/app/Models/Invoice.php b/app/Models/Invoice.php
index e793e96..5f4052c 100644
--- a/app/Models/Invoice.php
+++ b/app/Models/Invoice.php
@@ -4,28 +4,35 @@
 
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+use Illuminate\Database\Eloquent\SoftDeletes;
 
 class Invoice extends Model
 {
-    use HasFactory;
+    use HasFactory, SoftDeletes;
 
-    protected $fillable = [
-        'invoice_date',
-    ];
+    protected $guarded = [];
 
-    public function invoiceLines()
+    public function customer() : BelongsTo
     {
-        return $this->hasMany(InvoiceLine::class);
+        return $this->belongsTo(Customer::class);
     }
 
-    public function customer()
+    public function invoiceLines() : HasMany
     {
-        // return $this->belongsTo(Customer::class);
+        return $this->hasMany(InvoiceLine::class);
     }
 
-    public function price() {
+    public function getTotalPriceInCentsAttribute() : int
+    {
         return $this->invoiceLines->sum(function ($invoiceLine) {
-            return $invoiceLine->getTotal();
+            return $invoiceLine->totalPriceInCents;
         });
     }
+
+    public function getTotalPriceFormattedAttribute() : string
+    {
+        return number_format($this->getTotalPriceInCentsAttribute() / 100, 2);
+    }
 }
diff --git a/app/Models/InvoiceLine.php b/app/Models/InvoiceLine.php
index 3f69790..15452b0 100644
--- a/app/Models/InvoiceLine.php
+++ b/app/Models/InvoiceLine.php
@@ -4,29 +4,27 @@
 
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\SoftDeletes;
 
 class InvoiceLine extends Model
 {
-    use HasFactory;
+    use HasFactory, SoftDeletes;
 
-    protected $fillable = [
-        'invoice_id',
-        'product_id',
-        'quantity',
-    ];
+    protected $guarded = [];
 
-    public function invoice()
+    public function invoice(): BelongsTo
     {
         return $this->belongsTo(Invoice::class);
     }
 
-    public function getTotal()
+    public function getTotalPriceInCentsAttribute(): int
     {
-        return $this->quantity * $this->price;
+        return $this->quantity * $this->product->price_in_cents;
     }
 
-    public function getTotalFormatted()
+    public function getTotalPriceFormattedAttribute(): string
     {
-        return number_format($this->total, 2);
+        return number_format($this->getTotalPriceInCentsAttribute() / 100, 2);
     }
 }
diff --git a/database/factories/InvoiceFactory.php b/database/factories/InvoiceFactory.php
index 3edaad4..aeede9f 100644
--- a/database/factories/InvoiceFactory.php
+++ b/database/factories/InvoiceFactory.php
@@ -2,6 +2,7 @@
 
 namespace Database\Factories;
 
+use App\Models\Customer;
 use Illuminate\Database\Eloquent\Factories\Factory;
 
 /**
@@ -16,7 +17,10 @@ class InvoiceFactory extends Factory
      */
     public function definition(): array
     {
+        $cutomers = Customer::all();
+
         return [
+            'customer_id' => $cutomers->random()->id,
             'invoice_date' => $this->faker->date(),
         ];
     }
diff --git a/database/factories/InvoiceLineFactory.php b/database/factories/InvoiceLineFactory.php
index 16c48d4..67d3b72 100644
--- a/database/factories/InvoiceLineFactory.php
+++ b/database/factories/InvoiceLineFactory.php
@@ -2,6 +2,7 @@
 
 namespace Database\Factories;
 
+use App\Models\Product;
 use Illuminate\Database\Eloquent\Factories\Factory;
 
 /**
@@ -16,7 +17,11 @@ class InvoiceLineFactory extends Factory
      */
     public function definition(): array
     {
+
+        $products = Product::all();
+
         return [
+            'product_id' => $products->random()->id,
             'quantity' => $this->faker->numberBetween(1, 10),
         ];
     }
diff --git a/database/migrations/2024_01_26_090327_create_invoice_table.php b/database/migrations/2024_01_26_090327_create_invoice_table.php
index 66d0144..ad33217 100644
--- a/database/migrations/2024_01_26_090327_create_invoice_table.php
+++ b/database/migrations/2024_01_26_090327_create_invoice_table.php
@@ -14,8 +14,9 @@ public function up(): void
         Schema::create('invoices', function (Blueprint $table) {
             $table->id();
             $table->date('invoice_date');
-            $table->foreignId('customer_id')->nullable();
+            $table->foreignId('customer_id');
             $table->timestamps();
+            $table->softDeletes();
         });
     }
 
diff --git a/database/migrations/2024_01_26_091404_add_invoice_line.php b/database/migrations/2024_01_26_091404_add_invoice_line.php
index 771ef12..e55a9dc 100644
--- a/database/migrations/2024_01_26_091404_add_invoice_line.php
+++ b/database/migrations/2024_01_26_091404_add_invoice_line.php
@@ -18,6 +18,7 @@ public function up(): void
             $table->foreignId('product_id')->nullable();
             $table->integer('quantity');
             $table->timestamps();
+            $table->softDeletes();
         });
     }