Define the canonical cover, Database Management System

Assignment Help:

Define the Canonical cover

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

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

F_c 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 F_c than it is to test F itself.

Related Discussions:- Define the canonical cover

What is called query processing, What is called query processing? Query...

What is called query processing? Query processing refers to the range of activities included in extracting data from a database.

Dbms, Retrieve the S&S In-Chapter Database (in Microsoft Access format) fro...

Retrieve the S&S In-Chapter Database (in Microsoft Access format) from the text's Web site (or create the tables in Table 4-5 in a relational DBMS product). Write queries to answer

Database Management System, please give me introduction to full data in D B...

please give me introduction to full data in D B M S in a short assignment

Example of sequences, Example : Create a sequence named SEQSS that starts a...

Example : Create a sequence named SEQSS that starts at 105, has a step of 1 and can take maximum value as 2000. CREATE SEQUENCE SEQSS START WITH 105 INCREMENT BY 1 MAX VA

What does conceptual design work, What does conceptual design work? A c...

What does conceptual design work? A conceptual design involves modelling independent of the DBMS.

What is a transaction? and how does it differs from update, wh

Functional dependencies, CAR SALE (Car_id, Option_type, Option_listprice, S...

CAR SALE (Car_id, Option_type, Option_listprice, Sale_date, Option_discountedprice) This relation refers to options installed in cars (e.g., cruise control) that were sold at a de

Define the concept of object diagram, Define the concept of Object Diagram ...

Define the concept of Object Diagram An object diagram shows a set of the objects and their relationships with each other at a point of time. In a static view, object diagram

Unrepeatable reads-problems of concurrent transactions, Unrepeatable reads ...

Unrepeatable reads : Assume T7 reads X twice during its implementation. If it did not update X itself it could be very disturbing to see a dissimilar value of X in its next read. B

Differentiate between strict and rigorous two phase locking, Differentiate ...

Differentiate between strict two-phase and rigorous two-phase with conversion protocol Ans: Strict two-phase locking holds all its exclusive that is write locks until commit t

Write Your Message!

Name

Email id

Message

Verfication Code

User Account

All Pages