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

Search the name department number and salary of employees , Example : Searc...

Example : Search the name, department number and salary of employees drawing minimum salary in that department. SELECT ENAME, SAL, DEPTNO FROM EMP WHERE SAL IN (SELECT MI

Calculate the joint probability, Consider the following frequency counts o...

Consider the following frequency counts of some itemsets in a transaction database r : freq({A}, r) = 0.405 freq({B}, r) = 0.510 freq({C}, r) = 0.303 freq({A

Define instance and schema, Define instance and schema? Instance: Colle...

Define instance and schema? Instance: Collection of data stored in the data base at a certain moment is Schema: The overall design of the data base is known as the data base

Replicating data, Replicating Data One approach that may support effici...

Replicating Data One approach that may support efficient access to dissimilar applications as above may be to give access to every of the applications from dissimilar replicate

Sql, Events4Fun is an event management company in Europe with branches in S...

Events4Fun is an event management company in Europe with branches in South America as well. The company is well-known for its efficiency, good-quality services, and affordable char

Managing databases, 10A.53 Code an Oracle Database trigger to enforce the...

10A.53 Code an Oracle Database trigger to enforce the constraint that an employee can never change his or her department. 10A.54 Code an Oracle Database trigger to allow the

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

Queries, Find the names of all Albums that have more than 30 tracks. Result...

Find the names of all Albums that have more than 30 tracks. Result: (name: varchar(255))

RDBMS, DISADVANTAGES OF RDBMS

DISADVANTAGES OF RDBMS

What is the difference between primary key and a unique key, What's the dif...

What's the difference between a primary key and a unique key? Both primary key and unique key enforces uniqueness of the column on which they are explained. But by default prim

Write Your Message!

Name

Email id

Message

Verfication Code

User Account

All Pages