Hamish Burke | 2025-05-22
Related to: #databases
Functional Dependency
- For every pair of tuples in every possible instance, equality on the attributes in
forces equality on the attributes in are subsets of attributes
Equality on the attributes
- Two tuples have exactly the same values in every column of the attribute set in question
Example
STUDENT(studentID,name,major)
Tuples:
1,Alice,CS
2,Bob,EE
Functional dep:
studentID -> name, major
- Means every time its said studentID, it'll be the exact same name and major
Functional Dependency Closure
- Eg all valid FD's can be inferred using repeated applications of