First of all, I agree with Dev on the syntax. So, to your issue. If you have referential integrity, you have to delete from the referencinig tables first, followed by deleting from the referenced (central) table. How simple this may look, you may run into performance issues, most likely with the last delete. When you delete from the central table, referential integrity will be evaluated against all the referencing tables, possibly creating some 20 table or clustered index scans in your execution plan. If so, you may consider creating nonclustered indexes on the column(s) in the referencing tables which is a part of your foreign keys. I hope this helps.

As for space, deleting from tables do generate a lot of transaction log, beacuse SQL Server both logs the deletion and the old data so that the change can be rolled back, and it reserves enough space in the transaction log to be able to roll back. It is not uncommon for me to generate 10GB+ of transaction log for a delete transaction (from some ten tables).