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 deadlock detection and recovery, Explain Deadlock detection and rec...

Explain Deadlock detection and recovery Deadlock Detection - A deadlock is said to take place when there is a circular chain of transaction, every waiting for the release of a

Find out the names of all employees from database, Find out the names of al...

Find out the names of all employees who work for first Bank Corporation from database. SELECT EMPLOYEE_NAME FROM WORKS WHERE COMPANYNAME = ‘First Bank Corporation';

Economics, Economics: It is now usually accepted that it costs less to make...

Economics: It is now usually accepted that it costs less to make a system of smaller computers with the equivalent power of a one large computer. It is more cost-effective to get s

Explain alternate key, Explain Alternate key? Alternate Key - All the...

Explain Alternate key? Alternate Key - All the candidate keys except primary key are known as alternate keys.

Having clause-data manipulation language, Having clause This clause...

Having clause This clause is used for producing conditions on grouped information. Example: Find maximum salary and department number of those departments where maxim

What is meant by object identifiers, What is meant by object identifiers? ...

What is meant by object identifiers? Object-oriented systems use an object identifier to recognize objects. Object identifiers are unique: that is every object has a single ide

In case of entity integrity the primary key may be declared, In case of ent...

In case of entity integrity, the primary key may be declared? In a case of entity integrity primary key may be not Null.

Data replication, Data Replication "If a relation R has its copies kept...

Data Replication "If a relation R has its copies kept at two or more sites, then it is considered replicated". But why do we replicate a relation? There are several advan

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