Just as in its past versions, SharePoint 2010 allows you to create lists which contain lookup columns in other lists. This way, business users can define a new list item and populate its metadata based on fields from an existing list. In SharePoint 2010, business users can take advantage of new features allowing them to enforce referential integrity on the list items.
When attempting to delete a list item, if any items in other lists use this item to look up their values, the original item deletion can be prevented or the related item could automatically be deleted.
If you require setting up referential integrity in your organization's lists, you can speed up the provisioning process significantly using PowerShell.