What is functional dependency, Database Management System

Assignment Help:

 

A Functional dependency is described by X Y between two groups of attributes Y and X that are subsets of R specifies a constraint on the possible tuple that can make a relation state r of R. The constraint is for any two tuples t2 and t1 in r if t1[X] = t2[X] then they have t1[Y] = t2[Y]. This seems the value of X element of a tuple uniquely calculates the value of element Y.

 

 

1458_Functional Dependency.png


Related Discussions:- What is functional dependency

Entity identifier key attributes, An entity type usually has an attribute w...

An entity type usually has an attribute whose values are distinct for every individual entity in the collection. Such an attribute is known as a key attribute and its values can be

Query to list the employee name have 10000 salary, Consider employee table ...

Consider employee table of (i) and list names of department(s) for which average salary for department is more than 10,000. (SELECT d_name FROM dept WHERE d_code IN (SELECT d_c

What is thread splitting, What is Thread splitting A thread of cont...

What is Thread splitting A thread of control is a path by which a set of state diagrams on that a single object is active at a time. Objects are shared between threads

Entities, Entities Let us first be aware of the question: What are e...

Entities Let us first be aware of the question: What are entities? An entity is an object of concern used to show the things in the actual world, e.g., table, car, bo

What is an object design, What is an object design? Object design is a ...

What is an object design? Object design is a very interactive method, which decides the relationship among objects, classifies operations on classes, determines overall system

The result of the union operation between r1 and r2, The result of the UNIO...

The result of the UNION operation between R1 and R2 is a relation that includes? The result of the operation between R1 and R2 includes all the tuples of R1 and R2 which have c

Explain physical and logical independence, Define Physical and Logical inde...

Define Physical and Logical independence  Ans: Physical data independence: The ability to modify physical level without causing application program to be rewritten. Logic

Which two files are used during operation of the dbms, Which two files are ...

Which two files are used during operation of the DBMS? Data dictionary and transaction log are two files used during operation of the DBMS.

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

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