Data Modeling - (Derived|Calculated) Attribute (Derived Data)
1 - About
Derived is a property of:
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
2 - Articles Related
3 - UI
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.
4 - Examples
- Student Age,
- Account Balance,
- Number of courses taken.