<aside> ◻️ Review of last lecture: Deleting relations, large relations, data type, nested selects, views

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<aside> 🚧 Outline: Normalization: update anomaly, insertion anomaly, deletion anomaly, first normal form, functional dependence, second normal form, and example

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*https://www.notion.so/lavendershuo/Lecture-18-Normalization-03a84694d3a64e54a5c0622ae4332bac*

WHAT IS A GOOD RELATION DESIGN?

We have seen how to create a new relation from a given schema.

We know that the following rules must apply to relations:

1. Entity Integrity: For each tuple in a relation attributes that belong to the primary key must be non-null
2. Referential Integrity: All foreign key attribute values in a relation must be either null or correspond to a primary key value
3. Duplication of tuples in a relation is not allowed.
4. Next, we look at: - Normalization

Normalization

Normalization is a technique used to organize the data in a database.

• Normalization consists of a set of rules that all relations must follow for a database(DB) to be well structured.
• These rules are presented as sets of restrictions called NORMAL FORMS
• NORMALIZATION is the process of creating a DB that complies with these restrictions. We do that by normalizing each of the relations.
• Normal forms
  • 1NF (First Normal Form)
  • 2NF (Second Normal Form)
  • 3NF (Third Normal Form)
  • 4NF, 5NF, 6NF...... It's not always a good idea to normalize beyond 3NF.