Functional Dependencies(Cont.) K is a superkey for relation schema R if and only if K->R K is a candidate key for R if and only if K→R,and for no acK,→R Functional dependencies allow us to express constraints that cannot be expressed using superkeys.Consider the schema: inst dept (ID.name,salary.dept name,building,budget ) We expect these functional dependencies to hold: dept name->building and lD→building but would not expect the following to hold: dept name→salary Database System Concepts-6th Edition 8.13 @Silberschatz,Korth and SudarshanDatabase System Concepts - 6 8.13 ©Silberschatz, Korth and Sudarshan th Edition Functional Dependencies (Cont.) K is a superkey for relation schema R if and only if K → R K is a candidate key for R if and only if K → R, and for no   K,  → R Functional dependencies allow us to express constraints that cannot be expressed using superkeys. Consider the schema: inst_dept (ID, name, salary, dept_name, building, budget ). We expect these functional dependencies to hold: dept_name→ building and ID → building but would not expect the following to hold: dept_name → salary