Serialization: natural key for relations between context records

1 files changed, 12 insertions, 0 deletions

diff --git a/archaeological_context_records/models.py b/archaeological_context_records/models.py
index f0786e762..875a48019 100644
--- a/archaeological_context_records/models.py
+++ b/archaeological_context_records/models.py
@@ -884,6 +884,13 @@ class RelationType(GeneralRelationType):
         ordering = ('order', 'label')
 
 
+class RecordRelationsManager(models.Manager):
+    def get_by_natural_key(self, left_record, right_record, relation_type):
+        return self.get(left_record__uuid=left_record,
+                        right_record__uuid=right_record,
+                        relation_type__txt_idx=relation_type)
+
+
 class RecordRelations(GeneralRecordRelations, models.Model):
     MAIN_ATTR = 'left_record'
     left_record = models.ForeignKey(ContextRecord,
@@ -891,6 +898,7 @@ class RecordRelations(GeneralRecordRelations, models.Model):
     right_record = models.ForeignKey(ContextRecord,
                                      related_name='left_relations')
     relation_type = models.ForeignKey(RelationType)
+    objects = RecordRelationsManager()
     TABLE_COLS = [
         "left_record__label", "left_record__unit", "left_record__parcel",
         "relation_type",
@@ -922,6 +930,10 @@ class RecordRelations(GeneralRecordRelations, models.Model):
             ("view_recordrelation", "Can view all Context record relations"),
         ]
 
+    def natural_key(self):
+        return self.left_record.uuid, self.right_record.uuid, \
+               self.relation_type.txt_idx
+
 
 post_delete.connect(post_delete_record_relation, sender=RecordRelations)