Multiple choice technology architecture 

CREATE TABLE Purchaser{ 
      name string,
      credit_card integer (PRIMARY KEY), 
      address string 
}
CREATE TABLE Product{ 
    product_id integer (PRIMARY KEY), 
    product_name string 
}
CREATE TABLE Purchaser_Product{ 
    credit_card integer, 
    product_id integer, 
    purchase_date date 
}

Based on the sample code above, what is the primary key in the Purchaser_Product table?

  1. purchase_date

  2. Credit_card

  3. null

  4. credit_card & product_id

  5. product_id
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In the association table Purchaser_Product, a composite primary key consisting of credit_card and product_id is required to uniquely identify the relationship between a purchaser and a product, as neither column is marked as a unique primary key individually.

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