Define functional and multivalued dependencies, Database Management System

Assignment Help:

Define functional and multivalued dependencies.      

Ans:  A functional dependency is a assets of the semantics of the attributes in a relation. The semantics point out how attributes relate to one another, and identify the functional dependencies between attributes. While a functional dependency is available, the dependency is fixed as a constraint among the attributes. Refer a relation with attributes A and B, in which attribute B is functionally dependent on attribute A. If we know the value of A and we inspect the relation that holds this dependency, we will find out just only one value of B in all of the tuples which have a given value of A, at any moment in time. Note though, that for a given value of B there may be various different values of A. 

Multivalued Dependencies:  A multivalued dependency is an outcome of two independent 1: N relationships A: B and A: C being mixed in similar relation R(A,B,C)


Related Discussions:- Define functional and multivalued dependencies

Want massive amount of products imported through csv, OPENCART - Want Massi...

OPENCART - Want Massive amount of products Imported through CSV We have a massive list of products that would take completely too long to do data entry. We require a slick progr

Define object-relational systems, Define object-relational systems? Sy...

Define object-relational systems? Systems that give object-oriented extensions to relational systems are known as object-relational systems.

What is candidate key, What is Candidate Key Super Key or Candidate Ke...

What is Candidate Key Super Key or Candidate Key: It is such an attribute of a table that can uniquely recognize a row in a table. Generally they have unique values and can n

Update anomaly-data redundancy, Update Anomaly : This anomaly is occurred d...

Update Anomaly : This anomaly is occurred due to data redundancy. Redundant information makes updates more complex since, for example, varying the name of the instructor of MCS-014

Explain what is aggregation, Explain what is Aggregation? Aggregation:...

Explain what is Aggregation? Aggregation: Aggregation is an significant concept in database design whereas composite objects could be modelled during the design of database a

What is an operand, What is an Operand? The data on which the operation...

What is an Operand? The data on which the operation is to be performed is known as an Operand

Differance between open addressing and chaining collision, Differance betwe...

Differance between Open addressing and chaining for collision resolution ? In open addressing , proceeding from the occupied position specified by hash address the program che

Participation constraints, The participation Constraints shows whether the ...

The participation Constraints shows whether the existence of an entity depends on its being associated to another entity by the relationship type. There are two kinds of participat

What is meant by physical blocks, What is meant by Physical blocks? The...

What is meant by Physical blocks? The input and output operations are completed in block units. The blocks residing on the disk are referred to as physical blocks.

Related fields in a database are grouped in which form, Related fields in a...

Related fields in a database are grouped in which form? Related data fields in a database are grouped to form a data record. (A record is a collection of related fields)

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