Database Management
System
Functional Dependencies & Normalizatio
,Functional Dependencies
❖Users probably won’t understand that term “Functional Depen
important to ask right question.
❖If you known a particular employee number, can you establis
information, such as name?
❖If you can determine that the name is functionally dependent
employee number.
6/14/2023 2
,Functional Dependencies cont…
❖Another Question: Do you know the number of the department t
the employee is assign?.
❖If you can then we can say department no is functionally depen
employee number.
❖If a employee can be assigned to more than one department, you
not the know department number. So department no is not func
dependent on employee number.
6/14/2023 3
, Functional Dependencies cont…
❖Functional dependency concern the dependence of the value
attributes or set of attributes on those of another attribute or
attributes.
❖A FD is a property of the semantics or meaning of the attribu
relation.
❖Semantics indicate how attributes relate to one another and spe
FDs between attributes.
6/14/2023 4
System
Functional Dependencies & Normalizatio
,Functional Dependencies
❖Users probably won’t understand that term “Functional Depen
important to ask right question.
❖If you known a particular employee number, can you establis
information, such as name?
❖If you can determine that the name is functionally dependent
employee number.
6/14/2023 2
,Functional Dependencies cont…
❖Another Question: Do you know the number of the department t
the employee is assign?.
❖If you can then we can say department no is functionally depen
employee number.
❖If a employee can be assigned to more than one department, you
not the know department number. So department no is not func
dependent on employee number.
6/14/2023 3
, Functional Dependencies cont…
❖Functional dependency concern the dependence of the value
attributes or set of attributes on those of another attribute or
attributes.
❖A FD is a property of the semantics or meaning of the attribu
relation.
❖Semantics indicate how attributes relate to one another and spe
FDs between attributes.
6/14/2023 4
