Hello guys!

I need your help.
This is my query in mysql.
Code:
UPDATE `tblm`
SET UniqueString = NULL;

UPDATE `tblm`
SET UniqueString = TRIM(
	REPLACE (
		CONCAT(
			TES,
			idNode,
			idLINE,
			REPLACE (LINE_NAME, '`', '')
		),
		' ',
		''
	)
)
the composition of the key unique string prevents duplicate rows... the problem is that occurs when double row the query is stopped and error in output... would be possible in case double row delete last double row and not stopped the update query?
Code:
[Err] 1062 - Duplicate entry '60138282ARGO' for key 'UniqueString'
How can i do it?

Any help?
Thank you.