What is functional dependency, Database Management System

Assignment Help:

What is Functional Dependency?

A Functional dependency is shown by X Y among two sets of attributes X and Y that are subsets of R specifies a constraint on the possible tuple that can form a relation state r of R. The constraint is for any two tuples t1 and t2 in r if t1[X] = t2[X] then they have t1[Y] = t2[Y]. This means the value of X component of a tuple uniquely verifies the value of component Y.

Related Discussions:- What is functional dependency

Explain retrieval in qbe, Explain retrieval in QBE? Retrieval in QBE : ...

Explain retrieval in QBE? Retrieval in QBE : A "GUI" for expressing queries. Based on the Domain Relational Calculus (DRC) Actually invented before GUIs. Very co

Group by clauses-data manipulation language, Group By clauses • It is ...

Group By clauses • It is used to group database tuples on the basis of definite common attribute value like as employees of a department. WHERE clause still can be used

What is relationship, What is relationship? Give examples A relationshi...

What is relationship? Give examples A relationship is an association between several entities. Example: A depositor relationship associates a customer with every account tha

Lossless-join decomposition, Lossless-Join Decomposition Let us sh...

Lossless-Join Decomposition Let us show an intuitive decomposition of a relation. We require a better basis for deciding decompositions since intuition may not always be r

Example of alter table command, Example - ALTER TABLE emp MODIFY (empno NUM...

Example - ALTER TABLE emp MODIFY (empno NUMBER (7));

What is dml compiler, What is DML compiler? DML Compiler: Translates DM...

What is DML compiler? DML Compiler: Translates DML statements in a query language within low level instructions understandable through the query evaluation engine. Attempts to

What are the physical characteristics of magnetic disks, What are the physi...

What are the physical characteristics of magnetic disks? Ans: A magnetic disk is a circular plate or platter of plastic or metal that is coated with magnetizable material lik

MANAGEMWNT OF PRINCILES AND TECHNIQUES., HOW TO SOLVE THE LP Problems by si...

HOW TO SOLVE THE LP Problems by simplex method?z=x1+-3x2+2x3

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

Lack of standards and experience, Lack of standards and experience: The la...

Lack of standards and experience: The lack of standards has considerably limited the potential of distributed DBMSs. As well, there are no tools or methodologies to help users cha

Write Your Message!

Name

Email id

Message

Verfication Code

User Account

All Pages