identify a primary (key) attribute (field) for each entity, and then produce a d
ID: 3855244 • Letter: I
Question
identify a primary (key) attribute (field) for each entity, and then produce a diagram of the final logical model (include remaining functional dependencies, and referential integrity constraints)
If there are not enough natural primary (key) fields for all your entities ( tables) introduce the convenient fields synthesized just for those tables that you need a key field and do not have a natural field (e.g. item id for a table in an inventory database where no key field exists).
Create the diagram of your normalized model with a final listing of attributes with key attributes identified.
USE THE FOLLOWING INFORMATION
CUSTOMERID
name age gender
age over 21 yes or no
gender male or female
INVENTORYID
vendor name product name unitpurchased unitsold
ORDERID
date time placed time completed order total time paid payment method
payment method - cash, check, or charge
Explanation / Answer
CUSTOMER (customerid, name, age, gender)
INVENTORY (inventoryid, vendor_name, product)
INVENTORYPURCHASE (inventoryid, orderid, unitpurchased, unitsold)
ORDER (orderid, date_time_placed, time_completed, order_total_time, paid, payment_method,customerid)
PAYMENTMETHOD (payment_method)
Underlined text represents primary key, italic text represents foreign key.
Both italic and underlined means they fields are primary key of the table but actually foreign keys.
Underlining two different fields at the same table means they are composite keys.
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