Why Choosing the Right Primary Key is Critical in Database Design

In designing a "Customer" table, which field would be the best candidate for a primary key?

• A. CustomerName
• B. CustomerAddress
• C. CustomerNumber
• D. CustomerPhone

Answer: (C)

The best candidate for a primary key in the "Customer" table is CustomerNumber because it is typically unique to each customer. A primary key must uniquely identify each record in a database table, ensuring that no two records have the same identifier. CustomerNumber is generally designed to be a unique identifier assigned to each customer upon creation of their record. In contrast, CustomerName, CustomerAddress, and CustomerPhone may not provide the required uniqueness. For instance, multiple customers could have the same name (e.g., John Smith), share the same address (e.g., apartment buildings), or even have the same phone number in cases where family members or partners live together. These fields lack the distinctiveness needed for a primary key and could lead to ambiguity or data integrity issues if used in that capacity. Hence, CustomerNumber is the most suitable choice for serving as a primary key in the "Customer" table.

The Backbone of Database Design: Understanding Primary Keys

When you step into the realm of database design, one of the first concepts you'll bump into is that of a primary key. It’s a bit like finding the right key for your front door — without it, you can’t access your data properly! So, let’s explore why selecting the right primary key is crucial for maintaining a strong database structure.

What is a Primary Key, Anyway?

You know what? A primary key is essentially a unique identifier for each record in a database table. Just think of it this way: if your table is like a book, each primary key is like a page number that uniquely identifies that specific page’s content.

But why does that matter? If two pages have the same number, uh-oh, you might be flipping between two identical pages by mistake! This confusion can lead to serious data integrity issues.

Meet CustomerNumber: The Star of the Show

In the context of a