CBSE Class 11 Informatics Practices
Question 58 of 85
Database Concepts — Question 21
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Question Suppose all customers of a particular business live in states of which the city name is unique. Given the following description for customer data:
CUST_ID, CUST_NAME, STREET, CITY, STATE, PHONE
(a) List the most likely key for the primary key.
(b) List all the candidate keys and alternate keys.
(a) The most likely primary key is CUST_ID because it is a unique identifier assigned to each customer.
(b) CUST_ID, CITY attributes can be considered as candidate keys as both are unique to each customer.
CITY can serve as an alternate key because all customers live in states where the city names are unique.