minor fixes

datajoint/base_relation.py

@@ -146,10 +146,10 @@ def insert(self, rows, replace=False, ignore_errors=False, skip_duplicates=False
                         next(name for name in rows.heading if name not in heading))
                 except StopIteration:
                     pass
-            fields='`'+'`,`'.join(name for name in heading if name in rows.heading) + '`'
+            fields=list(name for name in heading if name in rows.heading)
             query = 'INSERT{ignore} INTO {table} ({fields}) {select}'.format( 
                ignore=" IGNORE" if ignore_errors or skip_duplicates else "",
-               fields=fields,
+               fields='`'+'`,`'.join(fields)+'`',
                table=self.full_table_name,
                select=rows.make_sql(select_fields=fields))
             self.connection.query(query)
@@ -280,7 +280,7 @@ def delete(self):
         for rel in delete_list.values():
             rel.restrict(False)    # initially prohibit all
         # apply restrictions
-        delete_list[self.full_table_name].set(self.restrictions)
+        delete_list[self.full_table_name].restrict(self.restrictions)
         for name, rel in delete_list.items():
             all_children = graph.children(name)
             semi = set(all_children)

datajoint/schema.py

@@ -5,7 +5,6 @@
 import re
 from . import conn, DataJointError, config
 from .erd import ERD
-from .jobs import JobsTable
 from .heading import Heading
 from .utils import user_choice, to_camel_case
 from .user_relations import Part, Computed, Imported, Manual, Lookup