Fds in relationships and teaches relationship, Database Management System

Assignment Help:

FDs in Relationships:

 Enrols Relationship: None as it is many to many

Teaches Relationship: Course code → Instructor

Instructor → Course code

The next question is:  How do we recognize the functional dependence in a database model?

Functional dependencies occur from the nature of the actual world that the database models. Often A and B are facts about an entity where A may be some identifier for the entity and B some characteristic. Functional dependencies cannot be automatically determined by studying one or more cases of a database. They can be determined only by a careful study of the actual world and a clear understanding of what every attribute means.

 There are no thumb rules for determining FDs.

Functional dependence is an vital concept and a large body of formal theory has been developed about it.

 


Related Discussions:- Fds in relationships and teaches relationship

Non-redundant cover and canonical cover, Given the following set of functio...

Given the following set of functional dependencies {cf?bg, g?d, cdg?f, b?de, d?c} defined on R(b,c,d,e,f,g) a.Find a non-redundant cover. b.Find a canonical cover.

What is conceptual model, What is conceptual model ? A conceptual model...

What is conceptual model ? A conceptual model is a independent of both hardware and software.

Describe different steps of object-oriented design process, Describe differ...

Describe different steps of the object-oriented design process.  The broad steps of the object-oriented design process are: a. Define context and modes of use of the system

What is meant by functional dependencies, What is meant by functional depen...

What is meant by functional dependencies? Consider a relation schema R and α C R and β C R. The functional dependency α ->β  holds on relational schema R if in any legal relati

Create a e-r diagram, Information about films holds information about movie...

Information about films holds information about movies, stars and studios. Movies have a title, year of production, length and the film type. Stars have a name and address. Studi

Distributed control and data sharing , Distributed Control and Data sharing...

Distributed Control and Data sharing: The geographical distribution of an organization can be showed in the distribution of the data; if a number of different sites are linked to e

A distributed transaction, A Distributed Transaction Let us demonstrate...

A Distributed Transaction Let us demonstrate the concept of a distributed transaction by considering a banking system having of three branches located in 3 different cities. Ev

What is database files , The database files accept the actual data and ...

The database files accept the actual data and are typically the biggest in size. Depending on their shape, the tables for all the user operation can go in one database file-but

Identify the candidate keys, Consider the following six relation schemes an...

Consider the following six relation schemes and their corresponding sets of functional dependencies. In each case identify a. All the candidate keys b. The highest normal for

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