This code works in SQL Server 2005 and above, because it uses the delete top (N) statement. Although using a cursor is not always a good idea but there are situations where we have to use it.
For most DBAs, normalization is an understood concept, a bread and butter bit of knowledge. However, it is not at all unusual to review a database design by a development group for an OLTP (OnLine Transaction Processing) environment and find that the schema chosen is anything but properly normalized. This article by Brian Kelley will give you the core knowledge to data model.