Change model - add PartParameterTemplate

InvenTree/part/admin.py

@@ -4,7 +4,7 @@ from import_export.admin import ImportExportModelAdmin
 from .models import PartCategory, Part
 from .models import PartAttachment, PartStar
 from .models import BomItem
-from .models import PartParameter
+from .models import PartParameterTemplate, PartParameter
 
 
 class PartAdmin(ImportExportModelAdmin):
@@ -31,13 +31,12 @@ class BomItemAdmin(ImportExportModelAdmin):
     list_display = ('part', 'sub_part', 'quantity')
 
 
-"""
 class ParameterTemplateAdmin(admin.ModelAdmin):
-    list_display = ('name', 'units', 'format')
-"""
+    list_display = ('name', 'units')
+
 
 class ParameterAdmin(admin.ModelAdmin):
-    list_display = ('part', 'name', 'data')
+    list_display = ('part', 'template', 'data')
 
 
 admin.site.register(Part, PartAdmin)
@@ -45,4 +44,5 @@ admin.site.register(PartCategory, PartCategoryAdmin)
 admin.site.register(PartAttachment, PartAttachmentAdmin)
 admin.site.register(PartStar, PartStarAdmin)
 admin.site.register(BomItem, BomItemAdmin)
+admin.site.register(PartParameterTemplate, ParameterTemplateAdmin)
 admin.site.register(PartParameter, ParameterAdmin)

InvenTree/part/migrations/0015_auto_20190820_0251.py

@@ -0,0 +1,37 @@
+# Generated by Django 2.2.4 on 2019-08-20 02:51
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('part', '0014_partparameter'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='PartParameterTemplate',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(help_text='Parameter Name', max_length=100)),
+                ('units', models.CharField(blank=True, help_text='Parameter Units', max_length=25)),
+            ],
+        ),
+        migrations.RemoveField(
+            model_name='partparameter',
+            name='name',
+        ),
+        migrations.AlterField(
+            model_name='partparameter',
+            name='data',
+            field=models.CharField(help_text='Parameter Value', max_length=500),
+        ),
+        migrations.AddField(
+            model_name='partparameter',
+            name='template',
+            field=models.ForeignKey(default=1, help_text='Parameter Template', on_delete=django.db.models.deletion.CASCADE, related_name='instances', to='part.PartParameterTemplate'),
+            preserve_default=False,
+        ),
+    ]

InvenTree/part/migrations/0016_auto_20190820_0257.py

@@ -0,0 +1,17 @@
+# Generated by Django 2.2.4 on 2019-08-20 02:57
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('part', '0015_auto_20190820_0251'),
+    ]
+
+    operations = [
+        migrations.AlterUniqueTogether(
+            name='partparameter',
+            unique_together={('part', 'template')},
+        ),
+    ]

InvenTree/part/models.py

@@ -1033,26 +1033,61 @@ class PartStar(models.Model):
         unique_together = ['part', 'user']
 
 
-class PartParameter(models.Model):
-    """ A PartParameter provides key:value pairs for extra 
+class PartParameterTemplate(models.Model):
+    """ A PartParameterTemplate provides a template for key:value pairs for extra 
     parameters fields/values to be added to a Part.
     This allows users to arbitrarily assign data fields to a Part
     beyond the built-in attributes.
 
     Attributes:
-        part: Link to a Part object
         name: The name (key) of the Parameter [string]
+        units: The units of the Parameter [string]
+    """
+
+    def __str__(self):
+        s = str(self.name)
+        if self.units:
+            s += " ({units})".format(units=self.units)
+        return s
+
+
+    name = models.CharField(max_length=100, help_text='Parameter Name')
+
+    units = models.CharField(max_length=25, help_text='Parameter Units', blank=True)
+
+
+class PartParameter(models.Model):
+    """ A PartParameter is a specific instance of a PartParameterTemplate.
+
+    Attributes:
+        part: Reference to a single Part object
+        template: Reference to a single PartParameterTemplate object
         data: The data (value) of the Parameter [string]
     """
 
+    def __str__(self):
+        return "{part} : {param} = {data}{units}".format(
+            part=str(self.part),
+            param=str(self.template.name),
+            data=str(self.data),
+            units=str(self.template.units)
+        )
+
+    class Meta:
+        # Prevent multiple instances of a parameter for a single part
+        unique_together = ('part', 'template')
+
     part = models.ForeignKey(Part, on_delete=models.CASCADE,
         related_name='parameters',
         help_text='Parent Part',
     )
 
-    name = models.CharField(max_length=100, help_text='Parameter Name')
+    template = models.ForeignKey(PartParameterTemplate, on_delete=models.CASCADE,
+        related_name='instances',
+        help_text='Parameter Template'
+    )
 
-    data = models.CharField(max_length=100, help_text='Parameter Value')
+    data = models.CharField(max_length=500, help_text='Parameter Value')
 
 
 class BomItem(models.Model):