Identifying relationship vs Mandatory non Identifying relationship

Hi Expert,

I'm confused for those two relationships, please explain,

Attached a file.

thanks in advance.
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oleggoldConnect With a Mentor Commented:
good examples:

-- Identifying relationship: Order --> Order Item; Primary Key of Order is Order Number; Primary Key of Order Item is Order Number (Foreign Key from Order) / Order Item Number. For identifying relationships, the parent is never optional (in other words, the inherited foreign key is NOT NULL).

-- Non-identifying relationship: Order Status --> Order; Primary Key of Order Status is Order Status Code; Primary Key of Order is Order Number; Order Status Code is a Foreign Key from Order Status in Order but not part of Order's primary key. If the business rule requires an Order to have an Order Status, the parent would not be optional (the inherited foreign key is NOT NULL); if not required, the parent would be optional (the inherited foreign key is NULLable).
Identifying relationship is manadatory  rel. that has to be present in both parent and child and that other attributes of the both entities rely on
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in the ex. above both can be mandatory ,1 is non-identifying
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