First pass implementation of cascading delete datajoint#15

datajoint/relation.py

@@ -1,4 +1,5 @@
 from collections.abc import Mapping
+from collections import defaultdict
 import numpy as np
 import logging
 import abc
@@ -82,10 +83,16 @@ def children(self):
 
     @property
     def references(self):
+        """
+        :return: list of tables that this tables refers to
+        """
         return self.connection.erm.references[self.full_table_name]
 
     @property
     def referenced(self):
+        """
+        :return: list of tables for which this table is referenced by
+        """
         return self.connection.erm.referenced[self.full_table_name]
 
     @property
@@ -187,8 +194,22 @@ def delete(self):
         User is prompted for confirmation if config['safemode']
         """
         relations = self.descendants
-        if self.restrictions and len(relations)>1:
-            raise NotImplementedError('Restricted cascading deletes are not yet implemented')
+        #if self.restrictions and len(relations)>1:
+        #    raise NotImplementedError('Restricted cascading deletes are not yet implemented')
+        restrict_by_me = defaultdict(lambda: False)
+        rel_by_name = {r.full_table_name:r for r in relations}
+        for r in relations:
+            for ref in r.references:
+                restrict_by_me[ref] = True
+
+        if self.restrictions is not None:
+            restrict_by_me[self.full_table_name] = True
+            rel_by_name[self.full_table_name]._restrict(self.restrictions)
+
+        for r in relations:
+            for dep in (r.children + r.references):
+                rel_by_name[dep]._restrict(r.project() if restrict_by_me[r.full_table_name] else r.restrictions)
+
         do_delete = True
         if config['safemode']:
             do_delete = False