I have two tables in parent-children relation. On update, I have to update the relation between those meaning new children of parent may be added or one of the child record can be deleted. I know I can use update to update value of the children but in this case I have to acutally update the relationship of childen to parent. One way to do this is to delete all children and parent record and insert new parent children again, but is there better way to update the relation?

How to update child records for parent? anyone?

Not quiet understand what you saying. Probably better if you show some code on how you currently updating your child/parent objects.