Data Modeling - (Derived|Calculated) Attribute (Derived Data)

Derived is a property of:

• a variable (scalar)
• or a of column (collection)

The value can be calculated or deduced from relationship Groupings or from the values of other variable. The value of a Derived variable changes constantly.

There is then a functional dependency between two variables.

Use Explicit data instead of derived data Jing Chen - Facebook - Hacker Way: Rethinking Web App Development at Facebook

Never focus just on the data in front of your eyes, or on derived variables, like percentages or rates Alberto Cairo - When doing data reporting, look at the raw numbers, not just at percentages —and write an accurate headline

This kind of dependency is really common in UI development when one action must refresh a part of the UI. It's often implemented with an observer pattern.

• Student Age,
• Account Balance,
• Number of courses taken.