Computer Sciene of Udayana State University

April 26, 2009

Fourth Normal Form (4NF) – MVD

Filed under: Computer Science — ignaga @ 1:23 AM

· MVD is a dependency caused

in most cases by having several multi-valued attributes in an 1NF relation.

Or, when a determinant, for example A, determines several sets of values (e.g. B and C) as shown below.1

  • MVD between attributes A, B, and C in a relation using the following notation:

A –> B

A –> C


· MVD can be further defined as being trivial or nontrivial.

MVD A –> B in relation R is defined as being trivial if (a) B is a subset of A or (b) A U B = R.

MVD is defined as being nontrivial if neither (a) nor (b) are satisfied.

Trivial MVD does not specify a constraint on a relation, while a nontrivial MVD does specify a constraint

Defined as a relation that is in BCNF and contains no nontrivial MVDs.

BranchNo –> Sname

BranchNo –> Oname

Decompose BranchStaffOwner into two tables




Leave a Comment »

No comments yet.

RSS feed for comments on this post. TrackBack URI

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Create a free website or blog at

%d bloggers like this: