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

Explain generalization and aggregation in e_r diagram, Explain the concept ...

Explain the concept of generalization and aggregation in E_R diagrams. Give one example for each one of them? Generalization: Consider extending the entity set account throug

Define shared locks, Define Shared locks? Ans: Shared lock: Throughout ...

Define Shared locks? Ans: Shared lock: Throughout concurrent execution of transactions, earlier than a transaction can access a data item, it has to obtain a lock on it. Now he

What are the benefits of document scanning, What are the benefits of docume...

What are the benefits of document scanning? Document scanning, in addition to being cost-efficient, also enhances productivity. This service enhances security as you set the pa

Strong entity set and weak entity set, Strong entity set and weak entity se...

Strong entity set and weak entity set? Strong entity set and weak entity set: A strong entity set has a primary key. All tuples in the set are distinguishable through that key.

Modular growth, Modular growth: In distributed environments, it is simple t...

Modular growth: In distributed environments, it is simple to expand. Latest sites can be added to the network without affecting the operations of other sites, as they are somewhat

Partial relation emp-get the details people with min salary, Let consider t...

Let consider the given partial relation EMP. Let us make some sub-queries for them EMPNO ENAME JOB SAL DEPTNO 7566

Describe the statement in sql which allows to change, Describe the statemen...

Describe the statement in SQL which allows to change the definition of a table? In SQL Alter statement is used to allow the changes the definition of a table.

A database administrator'', A database administrator''s responsibilities an...

A database administrator''s responsibilities and data contents

Describe difference between a one-to-many and a many-to-many, Describe the ...

Describe the difference between a one-to-many and a many-to-many relationship. Which logical data structures comprise one-to-many and which comprise many-to-many relationship?

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