Normalization Examples in DBMS

Solved Normalization Examples

Example 1 — Order Table

orders(order_id, product, product_price, customer, customer_city)

product_price depends on product (transitive); customer_city depends on customer. 3NF split:

orders(order_id, product_id, customer_id)
products(product_id, product, product_price)
customers(customer_id, customer, customer_city)

Example 2 — Marks Table

marks(roll, subject, marks, student_name)
Key = (roll, subject)

student_name depends only on roll → partial dependency. 2NF split:

marks(roll, subject, marks)
students(roll, student_name)

Summary

• Find the key, then check for partial and transitive dependencies.
• Split tables until each non-key column depends only on the whole key.

हल किए गए Normalization Examples

Example 1 — Order Table

orders(order_id, product, product_price, customer, customer_city)

product_price, product पर निर्भर (transitive); customer_city, customer पर। 3NF split:

orders(order_id, product_id, customer_id)
products(product_id, product, product_price)
customers(customer_id, customer, customer_city)

Example 2 — Marks Table

marks(roll, subject, marks, student_name)
Key = (roll, subject)

student_name सिर्फ roll पर निर्भर → partial dependency। 2NF split:

marks(roll, subject, marks)
students(roll, student_name)

सारांश

• Key ढूंढें, फिर partial और transitive dependencies check करें।
• Tables तब तक split करें जब तक हर non-key column पूरी key पर ही निर्भर हो।