Define functional and multivalued dependencies, Database Management System

Assignment Help:

Define functional and multivalued dependencies.      

Ans:  A functional dependency is a assets of the semantics of the attributes in a relation. The semantics point out how attributes relate to one another, and identify the functional dependencies between attributes. While a functional dependency is available, the dependency is fixed as a constraint among the attributes. Refer a relation with attributes A and B, in which attribute B is functionally dependent on attribute A. If we know the value of A and we inspect the relation that holds this dependency, we will find out just only one value of B in all of the tuples which have a given value of A, at any moment in time. Note though, that for a given value of B there may be various different values of A. 

Multivalued Dependencies:  A multivalued dependency is an outcome of two independent 1: N relationships A: B and A: C being mixed in similar relation R(A,B,C)


Related Discussions:- Define functional and multivalued dependencies

Give concurrent sub states diagram for the classroom, Give Concurrent sub s...

Give Concurrent sub states diagram for the classroom and exam held. In Figure, simultaneous substrates have been taken. After passing Minor 1 test you could give Minor 2 test. T

What is inheritance, What is inheritance? Define it in detail?  Inheri...

What is inheritance? Define it in detail?  Inheritance Inheritance can be at the levels of types, or at the level of tables we first consider inheritance of types, then i

Domain constraints, Domain Constraints Domain constraints are primarily...

Domain Constraints Domain constraints are primarily formed for defining the logically correct values for an attribute of a relation. The relation allows attributes of a relatio

What is log shipping, What is Log Shipping? Log shipping is the method ...

What is Log Shipping? Log shipping is the method of automating the backup of database and transaction log files on a production SQL server, and then restoring them onto a stand

Explain about sql server 2000, What is the difference between SQL Server 2...

What is the difference between SQL Server 2000 complete and differential backups? A complete backup makes a copy of the whole database. A differential backup creates a copy of

What is known as fudge factor, What is known as fudge factor? The numbe...

What is known as fudge factor? The number of partitions is enhanced by a small value called the fudge factor, which is usually 20 percent of the number of hash partitions compu

Which database object does not physically exist, Which database object does...

Which database object does not physically exist? A view database object does not physically exist.

Describe the advantage of state chart diagram, Describe the advantage of St...

Describe the advantage of State chart Diagram A state chart represents a state machine, emphasizing flow of control from one state to other. A state machine is a behaviour whi

Databases and data warehouses , Databases and data warehouses both are data...

Databases and data warehouses both are databases and both contains number of rows and columns of tables containing data. Data warehouse is really different from databases because d

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