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

What type of view of total database content, What type of view of total dat...

What type of view of total database content? Data base content Conceptual view of total database contain.

State the data flow diagram of functional model, State the data flow diagra...

State the data flow diagram of functional model Any action initiated by transition in the state diagram can be extended into an entire data flow diagram in functional model. Th

Define the term- state, State The position of object at any moment is ...

State The position of object at any moment is called state. An object can have many states depend upon time. After receiving some input instructions, the object can change its

Explain about database system structure, Explain about database system stru...

Explain about database system structure? Storage manager Authorization and integrity manager Transaction manager File manager Buffer manager Storage manager

Describe participation constraints, Describe Participation Constraints? ...

Describe Participation Constraints? Participation Constraints - The participation constraint exacts whether the existence of an entity depends on its being related to another

Explain the functions of data manager, Explain the functions of data manage...

Explain the functions of data manager? Functions of Data Manager : - Convert operations in user's queries coming directly through query processor or indirectly in an applicatio

Object-based models - data models, Object-based Models: Use objects as key ...

Object-based Models: Use objects as key data representation components . Examples:-   Entity-Relationship Model: It is a collection of real world objects known as entitie

Attribute preservation, Attribute Preservation This is a easy and obvio...

Attribute Preservation This is a easy and obvious necessity that includes preserving all the attributes that were there in the relation that is being decomposed.

gaps in sequence values can happen when-sequences, Gaps in sequence values...

Gaps in sequence values can happen when: -     A rollback happens that is when a statement changes are not accepted. -     When the system crashes -     When a sequence i

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