Consider relational schema and construct algebra query, Database Management System

Assignment Help:

Consider the following relational schema:
PERSON (SS#, NAME, ADDRESS)
CAR (REGISTRATION_NUMBER, YEAR, MODEL)
ACCIDENT (DATE, DRIVER, CAR_REG_NO)
OWNS (SS#, LICENSE)

Construct the subsequent relational algebra queries:
(i) Find out the names of persons who are included in an accident.
(ii) Find out the registration number of cars that were not involved in any accident.
Ans: (i) πNAME(PERSON) ∩ πDRIVER(ACCIDENT)
(ii) πREGISTRATION_NUMBER(CAR) - πCAR_REG_NO(ACCIDENT)


Related Discussions:- Consider relational schema and construct algebra query

Optimistic concurrency control, Optimistic Concurrency Control Is locki...

Optimistic Concurrency Control Is locking the only way to stop concurrency related problems? There exist some other ways too. One such way is known as an Optimistic Concurrency

ERD DIAGRAM, Law Associates is a large legal practice based in Sydney. You...

Law Associates is a large legal practice based in Sydney. You have been asked to design a data model for the practice based upon the following specification: The practice employs

Concurrency control, discuss the purpose of the concurrency control?

discuss the purpose of the concurrency control?

What are the various properties of relational tables, What are the various ...

What are the various properties of Relational tables? Relational tables have 6 properties: 1. Each row is unique. 2. Column values are of the same kind. 3. Values are

What is data model, A Data Model in software engineering is an abstract...

A Data Model in software engineering is an abstract model that organizes and documents the business data for interaction between team members and is used as a plan for creating

Differance between internal and external schema, Differance between interna...

Differance between internal and external schema? Internal and external schema: Internal Schema • Describes the physical storage structure • Uses a physical data model External

Describe logical data independence, Describe logical data independence ? ...

Describe logical data independence ? Logical Data Independence - It is the capacity to modify the conceptual schema without having to change external schemas or application p

Assignment - 1 - redoing to improve grades, Assignment #1 Data Management ...

Assignment #1 Data Management The questions on this exam are based on the Baxter Aviation case scenario. 1. (5 points) The systems analyst proposes the following two relationshi

Explain projection operation distribute over union operation, Illustrate th...

Illustrate the statement 'Projection operation distributes over the union operation'. Give an example.    Ans: Π L (E 1 ∪ E 2 ) = (Π L (E 1 )) ∪ (Π L (E 2 ))   This says th

Improved availability, Improved availability: The data in a distributed sys...

Improved availability: The data in a distributed system may be replicated so that it is at more than one site. Thus, the failure of a node or a communication link does not necessar

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