Time Index:  04:45-05:10:... Thanks for the explaination of the Global Relationship.  You know how to teach Richard.  I was thinking to "jump" right onto the Global Relationship.  There are more than just a global relationship after all to understand. So far no book has ever taught that kind of lesson.  Your teaching really inspires me a lot in term of the design of a database.

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Reply from Richard Rost:

They have their place... but you don't ALWAYS want to use them.

Take CUSTOMERS and ORDERS for example. If you set up a relationship with CASCADE DELETE set to ON, then any time you delete a customer, you delete all of his orders, which would totally mess up your accounting.

However, if you have ORDERS and LINE ITEMS (details) then you would definitely WANT to delete all of those items if the order itself is deleted. So it all depends on context.