viewnotes/247/Database Management System 10CS54 VTU unit 6

The Eduladder is a community of students, teachers, and programmers just interested to make you pass any exams. So we solve previous year question papers for you.
See Our team
Wondering how we keep quality?
Got unsolved questions?

Database-Management-Systems---10CS54-VTU-notes-->View question

Which Normal form is based on a concept of MVD?Database Management Systems - 10CS54 VTU notes (Jan 2013/July 2013/Jan 2014)

explain the same with example?

By:anonymousguy7799

Taged users:

Likes:
Be first to like this question

Dislikes:
Be first to dislike this question

Multivalued Dependencies and Fourth Normal Form (4NF) 4NF associated with a dependency called multi-valued dependency (MVD). MVDs in a relation are due to first normal form (1NF), which disallows an attribute in a row from having a set of values. MVD represents a dependency between attributes (for example, A, B, and C) in a relation, such that for each value of A there is a set of values for B, and a set of values for C. However, the set of values for B and C are independent of each other. MVD between attributes A, B, and C in a relation using the following notation  A - > - > B (A multidetermines B) A - > - > C

A multivalued dependency (MVD) X Y specified on R, where X, and Y are both subsets of R and Z = (R – (X Y)) specifies the following restrictions on r(R) t3[X]=t4[X]=t1[X]=t2[X] t3[Y] = t1[Y] and t4[Y] = t2[Y] t3[Z] = t2[Z] and t4[Z] = t1 [Z]
Fourth Normal Form (4NF) A relation that is in Boyce-Codd Normal Form and contains no MVDs. BCNF to 4NF involves the removal of the MVD from the relation by placing the attribute(s) in a new relation along with a copy of the determinant(s). A Relation is in 4NF if it is in 3NF and there is no multivalued dependencies.

Likes:
Be first to like this answer

Dislikes:
Be first to dislike this answer