fix the counting of deleted items. Issue #897

Author: dimitri-yatsenko

datajoint/table.py

@@ -351,10 +351,9 @@ def delete_quick(self, get_count=False):
     def _delete_cascade(self):
         """service function to perform cascading deletes recursively."""
         max_attempts = 50
-        delete_count = 0
         for _ in range(max_attempts):
             try:
-                delete_count += self.delete_quick(get_count=True)
+                delete_count = self.delete_quick(get_count=True)
             except IntegrityError as error:
                 match = foreign_key_error_regexp.match(error.args[0]).groupdict()
                 if "`.`" not in match['child']:  # if schema name missing, use self
@@ -383,7 +382,7 @@ def _delete_cascade(self):
                                                   match['pk_attrs'])))
                 else:
                     child &= self.proj()
-                delete_count += child._delete_cascade()
+                child._delete_cascade()
             else:
                 print("Deleting {count} rows from {table}".format(
                     count=delete_count, table=self.full_table_name))