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

System level permissions-data control, System level permissions : With the ...

System level permissions : With the use of data dictionary you can view them.       Let us take the table name as user_sys_privs (used in oracle).       DESCRIBE USER_SYS_PRI

What is a phantom deadlock, What is a Phantom Deadlock? In distributed...

What is a Phantom Deadlock? In distributed deadlock detection, the delay in propagating local information might cause the deadlock detection algorithms to recognize deadlocks

File organisation and its types, File Organisation And Its Types  Just ...

File Organisation And Its Types  Just as arrays, trees, lists and other data structures are used to execute data Organisation in main memory, a number of planning's are used to

Subclassing, In the ER diagram, one example of subclassing is depicted foll...

In the ER diagram, one example of subclassing is depicted following the Services entity. The subclasses Item Based and Time Based are created. The entity Services gains the attribu

Define cascading rollback, Define Cascading rollback The phenomenon whe...

Define Cascading rollback The phenomenon where a single transaction failure leads to a series of transaction rollbacks is known as Cascading rollback.

Database application and creation, Create Relational Database Model (RDM) f...

Create Relational Database Model (RDM) for Sailing bed and breakfast club Table_Name( attribute_1, attribute_2, attribute_3, ? ,attribute_x) Primary Key ( attribute_1, attribute_2)

Define a view and a trigger, Define a view and a trigger. Construct a view ...

Define a view and a trigger. Construct a view for the above relations that have the information about suppliers and the elements they supply. The view holds the S#, SNAME, P# , PNA

How does the system cope up with a record crash, How does the system cope u...

How does the system cope up with a record crash when recovery is going on after the first crash? Ans:  In a system the undo and redo operations are needed to be idempotent to c

What is a hash index, What is a hash index? A hash index organizes the ...

What is a hash index? A hash index organizes the search keys, with their associated pointers, into a hash file structure.

Database ass1, #quCreate a database design specification (Enhanced Entity R...

#quCreate a database design specification (Enhanced Entity Relationship Diagram (EERD) and Relational Data Model (RDM)) from the given business description. The RDM must be in 3rd

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