[Due soon] Please help! BCNF question. many thanks! Actually I\'ve posted this q

Question

[Due soon] Please help! BCNF question. many thanks!

Actually I've posted this question before at here.

https://www.chegg.com/homework-help/questions-and-answers/functional-dependency-bcnf-question-m-really-stuck-thanks-much-q24503182

but someone just copy-pased some random (unrelated) answer to my question. I feel really sad..

Is there anyone could help me. Really appreciate it!

Actually I've posted this question before at here.

https://www.chegg.com/homework-help/questions-and-answers/functional-dependency-bcnf-question-m-really-stuck-thanks-much-q24503182

but someone just copy-pased some random (unrelated) answer to my question. I feel really sad..

Is there anyone could help me. Really appreciate it!

Explanation / Answer

* regions(id, zip_code_served)

id -> zip_code_served

* customer(id, status, street, city, zip, region_id, cc_number)

id -> status, street, city, zip, region_id, cc_number
region_id -> id, status, street, city, zip, cc_number
cc_number -> id, status, street, city, zip, region_id

Here, In above non-trivial functional dependencies,
id, region_id, cc_number are unique. so we can derive many
other as well...
So,

id -> status,
id -> street etc.. are also non-trivial functional dependecy.
  
simillarly, region_id and cc_number also can derive other
non functional dependencies.

* orders(id, customer_id, total, qty)

id -> customer_id, total, qty
id -> customer_id
id ->total
id ->qty

customer_id -> id, total, qty
customer_id ->id
customer_id ->total
customer_id ->qty

*order_items(order_id, item_id, qty)

order_id -> item_id, qty
order_id ->item_id
order_id ->qty

item_id -> order_id, qty
item_id ->order_id
item_id ->qty

*items(id, price)

id ->price

2. Yes, it changes the functional dependency.
No, Schema will not be in BCNF.

Decomposion would be as follows-

id ->status
id ->streat, city, zip, region_id
id ->cc_number

3. No, no new functional dependency and yes, it will be in BCNF.
Since new requirement gives one to one relationship that is no mutlivalued entries for either zip or region.
there will not any change in functional dependencies.

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