Power table update issue

My ignition current version is 8.1.0RC1
In my version module power table I have 2 issue:
Problem 1:

if system.gui.confirm(u'记录将删除, 请确认?'):
	RequestDateTime=event.source.parent.getComponent('Power Table').RequestDateTime

	query="""
	DELETE FROM [dbo].[NTCOATest]
		  WHERE RequestDateTime=?
	"""
	system.db.runPrepUpdate(query,[RequestDateTime],'NTLog')
	
	table=event.source.parent.getComponent("Power Table")
	system.db.refresh(table,"data")

image
Here is the time what I get

SELECT 
       [WO_ID]
     , [RequestDateTime]
 

  FROM [NTLog].[dbo].[NTCOATest]
  WHERE RequestDate>='{Root Container.From.selectedLabel}'
  AND RequestDate<='{Root Container.To.selectedLabel}'
  ORDER BY WO_ID

Before 8.1.0RC1 , I can make this logic work, but after update to 8.1.0RC1 , I found it can’t work , due to the date format is changed, my question is in 8.1 version , if I have a datetime in the SQL table, if I want to update the query based on it’s timestamp, how to scripting ?

Problem 2:

	import system	
	id = self.data.getValueAt(rowIndex, "WO_ID")	
	query = "UPDATE [dbo].[NTCOATest] SET %s = ? WHERE [WO_ID] = ?" % (colName)
	args = [newValue, id]
	system.db.runPrepUpdate(query, args, 'NTLog')
	system.db.refresh(self, "data")

I have a table I scripting is able to update base on the upside logic


when I click the null column and do no change, then I click other column,

this null value will update to 0 ,how to avoid these problem happen?

thanks a lot