Define transitive dependencies, Database Management System

Assignment Help:

What do you understand by transitive dependencies? Define with an example any two problems that can take place in the database if transitive dependencies are available in the database.

 Ans:  Assume X, Y, and Z are the set of attributes. If X → Y and Y → Z afterwards the functional dependency X → Z is a transitive functional dependency. Alternatively, if a nonkey attribute is as well functionally dependent on the other nonkey attribute(s), then there is a transitive functional dependency. Transitive functional dependencies are as well cause the data redundancies and the other consequences. For instance, consider the subsequent relation:

CREATE TABLE CONTACTS

(CONTACT_ID NUMBER (5) PRIMARY KEY,

 L_NAME   VARCHAR (20),

 F_NAME   VARCHAR (20),

 COMPANY_NAME VARCHAR (20),

 COMPANY_LOCATION VARCHAR (50))

 In the following relation, all the nonkey attributes are functionally dependent on the primary key, that is CONTACT_ID. But, there is as well a transitive functional dependency exists in the relation - CONTACT_ID  COMPANY_LOCATION because CONTACT_ID → COMPANY_NAME and COMPANY_NAME →COMPANY_LOCATION.  The result of transitive dependency, there are anomalies in the above relation like this:

  • Insertion Anomaly - A new company cannot be inserted till a contact person has been assigned to that company.
  • Deletion Anomaly - If a company has just only one contact person and is deleted from the table, we will lose the information about that company, as the company information is related with that person.
  • Update Anomaly - If a company changes its location we will should make the changes in all the records in which the company name appears.

Related Discussions:- Define transitive dependencies

Create a query to produce single output-er model, This assignment concerns ...

This assignment concerns the Research database. The database ER model is shown above, where attributes are omitted for clarity. The relational model for the database is: Departm

ERD, online eductional management system ke diagram

online eductional management system ke diagram

Create a table to record a passengers information, Given the following rela...

Given the following relations TRAIN (NAME, START, DEST) TICKET (PNRNO., START, DEST, FARE) PASSENGER (NAME, ADDRESS, PNRNO.) Write SQL expressions for the following queries: No

Define data model, Define data model? A data model is a collection of c...

Define data model? A data model is a collection of conceptual tools for explaining data, data relationships, data semantics and consistency constraints.

Difference between functions along with or without grouping, Explain the di...

Explain the difference between using functions along with and without grouping attributes in relational algebra. Give examples. Ans: Group functions are used to group data of

Complete replication-data replication, Complete replication: It implies ma...

Complete replication: It implies maintaining of a whole copy of the database at every site. Thus, the reliability & availability and performance for query response are maximized.

Differentiate between horizontal and mixed partitioning, Question: In r...

Question: In relation to distributed database answer the following questions: (i) Give a brief definition of distributed database. Support your answer with an appropriate di

Explain dynamic two-phase locking, Explain Dynamic Two-Phase Locking H...

Explain Dynamic Two-Phase Locking Here a transaction locks a data item instantly earlier than any operation is applied on the data item.  After finishing all the operations on

What is theta join explain, What is theta join explain? Theta  Join  -...

What is theta join explain? Theta  Join  - The  theta  join  operation  is  an  extension  to  the  natural-join operation which permits us to merge selection and a Cartesian

Write short notes on domain relational calculus, Write short notes on domai...

Write short notes on domain relational calculus The domain relational calculus uses domain variables that take on values from an attribute domain rather than values for whole t

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