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

List and also explain the dissimilar stages of ddlc, List and also explain ...

List and also explain the dissimilar stages of DDLC ?

Define shadow paging, Define shadow paging. An alternative to log-based...

Define shadow paging. An alternative to log-based crash recovery method is shadow paging. This technique requires fewer disk accesses than do the log-based methods.

DW, #ques Define a job scheduling strategy that will meet business requirem...

#ques Define a job scheduling strategy that will meet business requirement of reporting availability by 6am CST for the following cubes? Show the job scheduling dependencies in a p

How nulls are treated in comparison operator, How nulls are treated in comp...

How nulls are treated in comparison operator? Along with comparison (relational) operators, the null values are ignored as we cannot derive the relation along with the given op

How can you start mysql server, How can you Start MySQL Server? To star...

How can you Start MySQL Server? To start the mysql program type it is name in the command- line prompt. After starting mysql program just display A welcome letter using the

Explain the equijoin, Explain the θ-join and equijoin Refer tables Car ...

Explain the θ-join and equijoin Refer tables Car and Boat which list models of cars and boats and their relevant prices. Assume a customer wants to buy a car and a boat, but sh

Define aggregate functions, Define Aggregate functions and what aggregate f...

Define Aggregate functions and what aggregate functions supported by the MySQL To calculate a summary value from a set of individual values and uses one of the functions known

Define redo logs, Redo Logs: Any database must have minimum two redo logs....

Redo Logs: Any database must have minimum two redo logs. These are the rules for the database; the redo logs record all modifies to the system objects or user objects. If any type

Linear commit protocol, With the linear commit protocol, sites are connecte...

With the linear commit protocol, sites are connected in a chain, and the subtransaction at the left-hand end of the chain initiates the protocol. Propose a crash recovery protocol

Candidate keys, Super keys of a relation can have extra attributes. Candida...

Super keys of a relation can have extra attributes. Candidate keys are minimal super key, i.e. such a key have no extraneous attribute. An attribute is known as extraneous if even

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