Follow PEP-0249 for Transaction and backends

issue4949
review19781002

company.py

@@ -82,9 +82,8 @@ class EmployeeCostPrice(ModelSQL, ModelView):
     @classmethod
     def __register__(cls, module_name):
         TableHandler = backend.get('TableHandler')
-        cursor = Transaction().cursor
         super(EmployeeCostPrice, cls).__register__(module_name)
-        table = TableHandler(cursor, cls, module_name)
+        table = TableHandler(cls, module_name)
 
         # Migration from 2.8 drop date_cost_price_uniq
         table.drop_constraint('date_cost_price_uniq')

timesheet.py

@@ -25,9 +25,9 @@ class TimesheetLine:
         Employee = pool.get('company.employee')
         TableHandler = backend.get('TableHandler')
 
-        cursor = Transaction().cursor
+        cursor = Transaction().connection.cursor()
         table = cls.__table__()
-        table_h = TableHandler(cursor, cls, module_name)
+        table_h = TableHandler(cls, module_name)
 
         migrate_cost_price = not table_h.column_exist('cost_price')