What are the Benefits of Database Normalization and How Does it Avoid Data Redundancy?

Normalized Databases: A Simplified Explanation

Explaining database normalization can be a challenge in plain English. But here's a practical breakdown:

Imagine you have a spreadsheet with employees' names and addresses. Instead of storing the country as a text field ("United States" for everyone), let's assign each country a numeric code in another table. So instead of repeating "United States" 100 times, we simply use the code "1". If a country splits into two (say, Yugoslavia becomes Serbia and Montenegro), we only have to update the country code table once.

But how do we handle multiple countries visited by each employee? Creating a single table with all the data would lead to duplication (e.g., "Faruz" visiting both "USA" and "Canada").

To avoid this, we normalize the database by creating three tables: "Persons" with employee details, "Countries" with country codes, and "VisitRelationships" that links persons to countries they've visited. This allows us to update employee or country information without creating duplicate rows.

In a job interview, key points to emphasize:

• Avoiding data duplication: Redundant information can lead to errors and inefficient storage.
• Second Normal Form (2NF): Removing duplicate rows by splitting data into related tables.
• Third Normal Form (3NF): Removing dependency within non-primary key attributes on other non-primary key attributes.

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