Full Functional Dependency (Databases)

A full functional dependency is a FD $Y\to Z$ where removal of any attribute from $Y$ means the FD does not hold anymore.

For example:

• $\{\text{SSN},\text{PNUMBER}\}\to \text{HOURS}$: full FD since neither SSN or PNUMBER into HOURS would hold.
• $\{\text{SSN},\text{PNUMBER}\}\to \text{ENAME}$: not a full FD, since $\text{SSN}\to \text{ENAME}$ also holds, this is called a partial dependency.