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

What are the drawbacks of shadow-paging technique, What are the drawbacks o...

What are the drawbacks of shadow-paging technique? The drawbacks of shadow paging is:- a) Commit Overhead b) Data fragmentation c)  Garbage collection

Difference between left outer join and right outer join, Difference between...

Difference between LEFT OUTER JOIN and RIGHT OUTER JOIN In left outer join tuples from the left-hand-side relation which do not match any tuple in the right-hand-side relation

Describe the candidate key functions, Describe the candidate key functions ...

Describe the candidate key functions ? Candidate Key and Alternate Key: In some instances, an entity will have more than one attribute which can serve as a primary key. Any key

Case-based online phone repair, please i request for your assistance in de...

please i request for your assistance in developing a case-based online phone repair

Example of relational operations, Consider the relation PERSON. If you want...

Consider the relation PERSON. If you want to display details of persons having age less than or equal to 30 than the select operation will be used as follows: σ AGE The resu

Case tools, explain at least five widly used case tools

explain at least five widly used case tools

Define tables students and teachers as sub tables of people, Write a query ...

Write a query to define tables students and teachers as sub tables of people? Create table students of student under people Create table teachers of teacher under people

Define lock, Define lock? Lock is the most common used to execute the r...

Define lock? Lock is the most common used to execute the requirement is to permit a transaction to access a data item only if it is currently holding a lock on that item.

Heterogeneous ddb and homogeneous ddb, Probelm: (a) A distributed datab...

Probelm: (a) A distributed database (DDB) is a collection of multiple, logically interrelated databases which are physically distributed over a computer network" (i) Give a

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