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Normalization (cont.)

5NF. 4NF. 3NF. 2NF. 1NF. Normalization (cont.). BCNF. Redundancy. Redundancy. Redundancy. Boyce-Codd Normal Form (BCNF). A relation is in BCNF if, and only if, It is in 3NF Every determinant is a candidate key .

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Normalization (cont.)

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  1. 5NF 4NF 3NF 2NF 1NF Normalization (cont.) BCNF Redundancy Redundancy Redundancy

  2. Boyce-Codd Normal Form (BCNF) • A relation is in BCNF if, and only if, • It is in 3NF • Every determinant is a candidate key. • BCNF is a refinement to third normal form, and tightens its duration.

  3. BCNF (cont.) • Had two or more candidate keys, such that • The candidate keys were composite, and • They overlapped (i.e. had at least one attribute in common)

  4. Example • Condition • Student register many courses • Instructor teach one course • Possible Key for this relation • Student + Instructor • Student + Course Functional Dependency {Student, Course} → Instructor {Instructor } → Course • Possible pair • {Student, Instructor} and { Student, Course } • {Course, Instructor} and { Course, Student } • {Instructor, Course} and { Instructor, Student }

  5. Example SIC( Student, Instructor, Course) SI( Student , Instructor ) IC(Instructor , Course)

  6. Example AProv Is the relation AProv in 2NF?

  7. Is it in 3 NF?

  8. Example SSP Is the relation SSP in 3NF?

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