feat: Enhance attribute model with JSONField and indexing

Changes the `value` field in `ProductAttribute` from `CharField` to `JSONField` to support multiple data types (string, number, boolean).
Adds database indexes to the `product` and `attribute` foreign keys in `ProductAttribute` to improve query performance.
Includes a data migration to safely convert existing string values to a JSON format.
Updates serializers and tests to handle various data types for attribute values.

Author: google-labs-jules[bot]

shop/migrations/0007_attribute_remove_product_height_and_more.py

@@ -0,0 +1,118 @@
+# Generated by Django 5.2 on 2025-11-29 18:42
+
+import django.core.validators
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+def migrate_product_dimensions_to_attributes(apps, schema_editor):
+    Product = apps.get_model('shop', 'Product')
+    Attribute = apps.get_model('shop', 'Attribute')
+    ProductAttribute = apps.get_model('shop', 'ProductAttribute')
+
+    # Create attributes if they don't exist
+    weight_attr, _ = Attribute.objects.get_or_create(name='Weight')
+    length_attr, _ = Attribute.objects.get_or_create(name='Length')
+    width_attr, _ = Attribute.objects.get_or_create(name='Width')
+    height_attr, _ = Attribute.objects.get_or_create(name='Height')
+
+    for product in Product.objects.all():
+        if product.weight is not None:
+            ProductAttribute.objects.create(product=product, attribute=weight_attr, value=str(product.weight))
+        if product.length is not None:
+            ProductAttribute.objects.create(product=product, attribute=length_attr, value=str(product.length))
+        if product.width is not None:
+            ProductAttribute.objects.create(product=product, attribute=width_attr, value=str(product.width))
+        if product.height is not None:
+            ProductAttribute.objects.create(product=product, attribute=height_attr, value=str(product.height))
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("shop", "0006_product_height_product_length_product_weight_and_more"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="Attribute",
+            fields=[
+                (
+                    "id",
+                    models.BigAutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+                ("name", models.CharField(max_length=100, unique=True)),
+                ("description", models.TextField(blank=True, null=True)),
+            ],
+        ),
+        migrations.CreateModel(
+            name="ProductAttribute",
+            fields=[
+                (
+                    "id",
+                    models.BigAutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+                ("value", models.CharField(max_length=255)),
+                (
+                    "attribute",
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE, to="shop.attribute"
+                    ),
+                ),
+                (
+                    "product",
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        related_name="attributes",
+                        to="shop.product",
+                    ),
+                ),
+            ],
+            options={
+                "unique_together": {("product", "attribute")},
+            },
+        ),
+        migrations.RunPython(migrate_product_dimensions_to_attributes),
+        migrations.RemoveField(
+            model_name="product",
+            name="height",
+        ),
+        migrations.RemoveField(
+            model_name="product",
+            name="length",
+        ),
+        migrations.RemoveField(
+            model_name="product",
+            name="weight",
+        ),
+        migrations.RemoveField(
+            model_name="product",
+            name="width",
+        ),
+        migrations.AlterField(
+            model_name="product",
+            name="price",
+            field=models.DecimalField(
+                decimal_places=2,
+                max_digits=10,
+                validators=[django.core.validators.MinValueValidator(0.0)],
+            ),
+        ),
+        migrations.AlterField(
+            model_name="product",
+            name="stock",
+            field=models.IntegerField(
+                validators=[django.core.validators.MinValueValidator(0)]
+            ),
+        ),
+    ]

shop/migrations/0008_category_attributes.py

@@ -0,0 +1,20 @@
+# Generated by Django 5.2 on 2025-11-29 18:56
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("shop", "0007_attribute_remove_product_height_and_more"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="category",
+            name="attributes",
+            field=models.ManyToManyField(
+                blank=True, related_name="categories", to="shop.attribute"
+            ),
+        ),
+    ]

shop/migrations/0009_alter_productattribute_value_and_more.py

@@ -0,0 +1,43 @@
+# Generated by Django 5.2 on 2025-11-29 19:09
+import json
+from django.db import migrations, models
+
+def convert_value_to_json(apps, schema_editor):
+    ProductAttribute = apps.get_model('shop', 'ProductAttribute')
+    for pa in ProductAttribute.objects.all():
+        try:
+            # Attempt to parse as a number first
+            value = float(pa.value)
+        except (ValueError, TypeError):
+            # Fallback to string
+            value = pa.value
+
+        pa.value = json.dumps(value)
+        pa.save(update_fields=['value'])
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("shop", "0008_category_attributes"),
+    ]
+
+    operations = [
+        migrations.RunPython(convert_value_to_json, reverse_code=migrations.RunPython.noop),
+        migrations.AlterField(
+            model_name="productattribute",
+            name="value",
+            field=models.JSONField(),
+        ),
+        migrations.AddIndex(
+            model_name="productattribute",
+            index=models.Index(
+                fields=["product"], name="shop_produc_product_979956_idx"
+            ),
+        ),
+        migrations.AddIndex(
+            model_name="productattribute",
+            index=models.Index(
+                fields=["attribute"], name="shop_produc_attribu_8385ae_idx"
+            ),
+        ),
+    ]

shop/models.py

@@ -20,6 +20,8 @@ class Meta:
 
 
 class Category(SluggedModel):
+    attributes = models.ManyToManyField('Attribute', blank=True, related_name='categories')
+
     class Meta:
         verbose_name = "Category"
         verbose_name_plural = "Categories"
@@ -73,10 +75,6 @@ class Product(SluggedModel):
     objects = models.Manager()
     in_stock = InStockManager()
     tags = TaggableManager(through=CustomTaggedItem)
-    weight = models.DecimalField(max_digits=10, decimal_places=2, null=True, blank=True, validators=[MinValueValidator(0.0)])
-    length = models.DecimalField(max_digits=10, decimal_places=2, null=True, blank=True, validators=[MinValueValidator(0.0)])
-    width = models.DecimalField(max_digits=10, decimal_places=2, null=True, blank=True, validators=[MinValueValidator(0.0)])
-    height = models.DecimalField(max_digits=10, decimal_places=2, null=True, blank=True, validators=[MinValueValidator(0.0)])
 
     class Meta:
         verbose_name = "Product"
@@ -171,3 +169,27 @@ def save(self, *args, **kwargs):
 
     def __str__(self):
         return f"Review by {self.user} for {self.product} - {self.rating} stars"
+
+
+class Attribute(models.Model):
+    name = models.CharField(max_length=100, unique=True)
+    description = models.TextField(blank=True, null=True)
+
+    def __str__(self):
+        return self.name
+
+
+class ProductAttribute(models.Model):
+    product = models.ForeignKey(Product, related_name='attributes', on_delete=models.CASCADE)
+    attribute = models.ForeignKey(Attribute, on_delete=models.CASCADE)
+    value = models.JSONField()
+
+    class Meta:
+        unique_together = ('product', 'attribute')
+        indexes = [
+            models.Index(fields=['product']),
+            models.Index(fields=['attribute']),
+        ]
+
+    def __str__(self):
+        return f"{self.product.name} - {self.attribute.name}: {self.value}"