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Explain like I’m five: database Normalization

Normalization: It’s like organizing your wardrobe to avoid repeated or unnecessary items. This way, when you want to add a new shirt or change an old one, you can easily do it without messing up the entire wardrobe or having unexpected issues like two identical shirts.

Database Example: Let’s say you have a table that lists all purchases you’ve made. If you put the seller’s full details (like address, contact, etc.) for every single purchase, it’s redundant. If the seller’s address changes, you’d have to update it in multiple places.

Normal Forms: These are like the steps or levels of how well-organized your wardrobe is.

  1. 1st Normal Form (1NF): Make sure every section in your wardrobe has only one type of item. So, socks in one drawer, shirts on one shelf. No mixing.
    Database Example: Ensure each column in your table has only one type of information. For instance, don’t have a column “Name” where you store both first and last names together like “John Smith”. Instead, have two columns: “FirstName” and “LastName”.
  2. 2nd Normal Form (2NF): Now, ensure there’s no unnecessary repetition. For example, if you have a tag on each shirt saying it’s a shirt, that’s repetitive since you already know it’s the shirt section. Database Example: Split data into separate tables if columns are frequently repeated. Let’s say your purchase table has the seller’s details for every purchase. Instead, create a separate “Sellers” table, and link to it from your purchase table using a SellerID.
  3. 3rd Normal Form (3NF): Make sure everything in the wardrobe is only about the clothes. For example, you shouldn’t have a note about buying milk in your shirt pocket. Keep unrelated things separate.
    Database Example: Any information in a table should only be about the main topic of the table. If your “Sellers” table started having columns about what the sellers like to eat for breakfast, that’s unrelated to being a seller and should be in a different table.

Normalizing an Actual Database Table:

  1. Identify Each Piece of Data: Understand what each column in your table represents.
  2. Break Down Columns with Multiple Types of Information: If one column stores multiple types of information, split it.
  3. Remove Repetitions: If you find multiple rows repeating the same data, think about how to create separate tables to reduce this repetition.
  4. Create Relationships: Once you have separate tables, link them using keys (like SellerID or ProductID).
  5. Review and Refine: As you use the database, you might discover more ways to optimize and reduce redundancy. Regularly review and adjust as needed.

In short, normalization and these normal forms help keep your database (or wardrobe) tidy, organized, and easy to manage.