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

Extended star schema, Northwind Pty Ltd sells a variety of food products th...

Northwind Pty Ltd sells a variety of food products throughout the world. They want to use the reporting features of SAP''s Business Information Warehouse to better understand thei

Write short notes on index structure of files, WRITE SHORT NOTES ON INDEX S...

WRITE SHORT NOTES ON INDEX STRUCTURE OF FILES? There are two basic parts of indices 1.   Ordered indices 2.   Hash indices Every technique must be evaluated on the bas

Define thomas write rule, Define Thomas write rule Thomas' write rule: ...

Define Thomas write rule Thomas' write rule: The Thomas' write rule is a modification of timestamp-ordering protocol for concurrency control. Assume that transaction T i issue

List two restrictions that are applied on the modification, List two restri...

List two restrictions that are applied on the modification (updation, insertion or deletion) of base tables through view.  Ans: The two restrictions are: 1. If a view

Develop a java application, 1 - Serial RS232 comm port comunication 2 - ...

1 - Serial RS232 comm port comunication 2 - NanoHTTPD serving a few processed pages 3 - System tray application to indicate status and access configuration forms 4 - SQLit

MANAGEMWNT OF PRINCILES AND TECHNIQUES., HOW TO SOLVE THE LP Problems by si...

HOW TO SOLVE THE LP Problems by simplex method?z=x1+-3x2+2x3

Hoework, Farmer Bob, Farmer Jane and Farmer Jose run a cow farming co-op. ...

Farmer Bob, Farmer Jane and Farmer Jose run a cow farming co-op. For every cow they keep the cow’s name, age (or date of birth), breed and numbered plastic ear tag. The each of t

Define hot backup, Hot Backup: Some sites cannot terminate the database wh...

Hot Backup: Some sites cannot terminate the database while creating a backup copy of the files. The cold backup is not a reliable option. So different kinds of backing up database

Writing a pl/sql program, Problem 1. Create a PL/SQL program to insert ...

Problem 1. Create a PL/SQL program to insert data into student table and display the details of the student having Reg.No 1010 Writing a PL/SQL program to Insert data

What is relational dbms, What is Relational DBMS This is our subject of...

What is Relational DBMS This is our subject of study. A DBMS is relational if the data is organized into relations, that is, tables. In RDBMS, all data are kept in the well-kno

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