Introduced PartRelated model to store part relationships

InvenTree/part/migrations/0052_partrelated.py

@@ -0,0 +1,22 @@
+# Generated by Django 3.0.7 on 2020-10-15 18:51
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('part', '0051_bomitem_optional'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='PartRelated',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('part_1', models.ForeignKey(on_delete=django.db.models.deletion.DO_NOTHING, related_name='related_parts_1', to='part.Part')),
+                ('part_2', models.ForeignKey(on_delete=django.db.models.deletion.DO_NOTHING, related_name='related_parts_2', to='part.Part')),
+            ],
+        ),
+    ]

InvenTree/part/models.py

@@ -1254,6 +1254,25 @@ class Part(MPTTModel):
 
         return self.get_descendants(include_self=False)
 
+    def fetch_related_parts(self):
+        """ Return all related parts """
+
+        related_parts = []
+
+        parts_1 = self.related_parts_1.filter(part_1__id=self.pk)
+
+        parts_2 = self.related_parts_2.filter(part_2__id=self.pk)
+
+        for part in parts_1:
+            # Append 
+            related_parts.append(part.part_2)
+
+        for part in parts_2:
+            # Append 
+            related_parts.append(part.part_1)
+
+        return related_parts
+
 
 def attach_file(instance, filename):
     """ Function for storing a file for a PartAttachment
@@ -1723,3 +1742,35 @@ class BomItem(models.Model):
         pmax = decimal2string(pmax)
 
         return "{pmin} to {pmax}".format(pmin=pmin, pmax=pmax)
+
+
+class PartRelated(models.Model):
+    """ Store and handle related parts (eg. mating connector, crimps, etc.) """
+
+    part_1 = models.ForeignKey(Part, related_name='related_parts_1', on_delete=models.DO_NOTHING)
+
+    part_2 = models.ForeignKey(Part, related_name='related_parts_2', on_delete=models.DO_NOTHING)
+
+    def create_relationship(self, part_1, part_2):
+
+        parts = Part.objects.all()
+
+        # Check if part exist
+        if (part_1 in parts and part_2 in parts) and (part_1 is not part_2):
+            # Add relationship
+            self.part_1 = part_1
+            self.part_2 = part_2
+            self.save()
+
+            return True
+        else:
+            return False
+
+    @classmethod
+    def create(cls, part_1, part_2):
+        related_part = cls()
+        related_part.create_relationship(part_1, part_2)
+        return related_part
+
+    def __str__(self):
+        return f'{part_1} <-> {part_2}'