What is a recursive relationship, Database Management System

Assignment Help:

Question:

(a) Can a set of data requirements be correctly modelled by two or more different ER diagrams? Explain your answer. You may use a small example, if you think it will help your explanation.

(b) What is a recursive relationship? Give an example of a many to many recursive relationship.

This question refers to the Appendix where the relational schema for an online DVD rental system is defined.

(c) Express the following queries using relational algebra:

(i) Find all DVD titles with their certificate being ‘15' and their type name being ‘Drama'

(ii) Find names of all members and the titles of DVDs, which they have rented between 1st

May 2007 and 31st
May 2007

(iii) Find names of all the members who have rented any DVD with type name ‘Comedy' but not any DVD with Type name ‘Action'


Related Discussions:- What is a recursive relationship

Entity relationship model, Let us first look into some of the important fea...

Let us first look into some of the important features of ER model. Entity relationship model is a high-level conceptual data model. It permits us to define the data invo

Illustrate the cardinality of relationship, Cardinality of Relationship ...

Cardinality of Relationship One-to-One Only one entity of the first set is linked to only one entity of the second set. E.g. A teacher teaches a student. Only one teacher

Explain the term - adjustment of inheritance, Explain the term - Adjustment...

Explain the term - Adjustment of inheritance The inheritance can be enlarged as object design progresses by changing class structure. The designer should do: i) Adjust or r

Hangman, a method named WonGame that checks each letter in the word is matc...

a method named WonGame that checks each letter in the word is matched by its label

Data, Explain three main attributes of data.

Explain three main attributes of data.

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

Database for Managers, I have to create a database about anything of my cho...

I have to create a database about anything of my choice. It has to contain 4 queries, and 4 forms. It can be anything as simple as a shoe inventory with numbers - is this a service

Durability-transaction , Durability : This property necessitates that once ...

Durability : This property necessitates that once a transaction has committed, the changes made by it be never lost because of subsequent failure. Thus, a transaction is also a bas

ERD, A student entity type has the following attributes,name..

A student entity type has the following attributes,name..

Write short notes on transaction state, Write short notes on transaction st...

Write short notes on transaction state? A transaction may not always complete its implementation successfully such a transaction is termed aborted A transaction must be in o

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