Define multivalued dependency and 4nf, Database Management System

Assignment Help:

Define multivalued dependency and 4NF.

 Ans:  Multivalued Dependency - Assume R be a relation schema and let α ⊆ R and β ⊆ R. The multivalued dependency 

α →→β 

 holds on R if, in any type of legal relation r(R), for all pairs of tuples t1 and t2 in r like that 

t1[α] = t2[α], there exist tuples t3 and t4 in r like

t1[α] = t2[α] = t3[α] = t4[α]

t3[β] = t1[β]

t3[R - β] = t2[R - β]

t4[β] = t2[β]

t4[R - β] = t1[R - β]

 Fourth Normal Form (4 NF) - A relation schema R is in 4NF regarding to a set D of functional and multivalued dependencies if, for all multivalued dependencies in D+ of the

form α →→β, in which α ⊆ R and β ⊆ R, at least one of the subsequent holds:

  • α→→β is a trivial multivalued dependency,
  • α is a superkey for schema R.

Related Discussions:- Define multivalued dependency and 4nf

ER Diagram, Hi I have got an assignment for making an er diagram for market...

Hi I have got an assignment for making an er diagram for market management software can any budy help me?

Information infrasture, what benefit can a company gain by managing its own...

what benefit can a company gain by managing its own infrasture and services

Explain about data independence, Data Independence This brings us to ou...

Data Independence This brings us to our next topic: data independence. It is the property of the database which tries to make sure that if we make any change in any level of sc

Equijoin, When every condition appears with equality condition (=) only. c)...

When every condition appears with equality condition (=) only. c)   Natural join (denoted by R*S) When two join attributes have the similar name in both relations. (Tha

What is conceptual schema, What is Conceptual Schema? Conceptual Schema...

What is Conceptual Schema? Conceptual Schema - Conceptual schema elaborates the structure of the overall database for a community of users. It hides the details of physical sto

Heterogeneous ddb and homogeneous ddb, Probelm: (a) A distributed datab...

Probelm: (a) A distributed database (DDB) is a collection of multiple, logically interrelated databases which are physically distributed over a computer network" (i) Give a

What is outer join, What is Outer join?  They can be employed while we ...

What is Outer join?  They can be employed while we want to keep all the tuples in R, or all those in S or all those in both relations in the result of the JOIN in spite of of w

How relational calculus is different from relational algebra, How Relationa...

How Relational Calculus is different from Relational Algebra? What do understand by TRC queries and DRC queries?  Ans: Relational calculus contain two calculi, the tuple relati

#title using the invoice, using the invoice table shown below,write the rel...

using the invoice table shown below,write the relational schema,draw a dependencies,inclunding all partial and transitive dependencies.assume that the table does not contain repeat

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd