Define the canonical cover, Database Management System

Assignment Help:

Define the Canonical cover

Ans: A canonical cover Fc for F is a set of dependencies like F logically implies all dependencies in Fc, and Fc logically entails all dependencies in F. Fc must have the subsequent properties:

  • No functional dependency in Fc consists of extraneous attribute
  • Every left side of a functional dependency in Fc is unique. Which is, there are no two dependencies α1→ β1 and α2→β2 in Fc such that α1 = α2.

 Fc is minimal in certain sense - it does not consist of extraneous attributes, and it combines functional dependencies with similar left side. It is cheaper to test Fc than it is to test F itself.


Related Discussions:- Define the canonical cover

Explain interfaces for parametric users, Explain Interfaces for parametric ...

Explain Interfaces for parametric Users? Interfaces for Parametric Users - Parametric users, such as bank tellers, frequent have a little set of operations in which they must p

Explain recovery process after system failure, Explain recovery process aft...

Explain recovery process after system failure using checkpoint. Ans: Checkpoint scheme or method is an extra component of the log based recovery system. This scheme is used to

Although how will the system recover, Although how will the system recover ...

Although how will the system recover The selection of REDO or UNDO for a transaction for the recovery is completed on the basis of the state of the transactions. This state is

Datamodels, explain thee diffrent types of data models

explain thee diffrent types of data models

List the armstrong axioms for functional dependencies, List the Armstrong's...

List the Armstrong's axioms for functional dependencies.  What do you understand by soundness and completeness of these axioms?      Ans: The Armstrong's axioms are: F1:

Define the method of recursion, What is recursion? Is it possible for a sto...

What is recursion? Is it possible for a stored procedure to call itself or recursive stored procedure?  How many levels of SP nesting is possible? Recursion is method of proble

Intersection, If R1 and R2 are two union compatible relations or functions,...

If R1 and R2 are two union compatible relations or functions, then the result of R3 = R1 ∩R2 is the relation that contains all tuples that are in both the relations In other words,

What are the states of transaction, What are the states of transaction? ...

What are the states of transaction? The states of transaction are:- a) Active b) Partially committed c) Failed d) Aborted e )Committed   f) Terminated

What is called as recursive partitioning, What is called as recursive parti...

What is called as recursive partitioning? The system repeats the splitting of the input unless each partition of the build input fits in the memory. Such partitioning is known

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