Define query by example, Database Management System

Assignment Help:

Define Query by Example

QBE is a query language relies upon domain calculus and has two dimensional syntax. The queries are written in the horizontal and vertical dimensions of table. Queries are made by entering an instance of a possible answer in a skeleton table as displayed in the following diagram: 

1387_Query-By-Example.png

Conditions particular in a single row are ANDed and conditions illustrated in separate rows are ORed. The tuple operations are P., I ., etc., for PRINT, insert commands, resp. The variable names are illustrated by preceding their name with an underscore. QBE as well provides a "conditions" box to specify additional constraints that is why the conditions that cannot be added in a Skelton table can be entered in the conditions table. The aggregation operations such as max., min, sum. etc. are also provided by QBE.


Related Discussions:- Define query by example

What is the role of order by clause, What is the role of ORDER By Clause? ...

What is the role of ORDER By Clause? ORDER BY clause: The ORDER BY clause permits you to sort the records in your result set. The ORDER BY clause can just be used in select s

Assignment, Birla Institute of Technology & Science, Pilani Work-Integrated...

Birla Institute of Technology & Science, Pilani Work-Integrated Learning Programmes Division Second Semester 2012-2013 EC-1 Assignment 2 (7.5% of the grade) Course No. : SS ZG

DISTIBUTED DATABASE, Define physical image of a global relation at a site

Define physical image of a global relation at a site

Update operations, The Update Operations : Update operations are used fo...

The Update Operations : Update operations are used for altering database values. The constraint violations faced by this operation are logically the similar as the problem faced

Database integrity and database security, Question : (a) Differentiate ...

Question : (a) Differentiate between database integrity and database security (b) Database security involves measures to avoid loss of privacy and loss of confidentiality. D

Replication-design of distributed databases, Replication : It is definite a...

Replication : It is definite as a copy of a relation. Every replica is stored at a dissimilar site. The alternative to replication is to store only single copy of a relation which

Define the unique constraints for the table client, Define the following co...

Define the following constraints for the table client. (i) BAL_DUE must be at least 1000. (ii) NAME is a unique key. (i)ALTER TABLE CLIENT ADD CONSTRAINT CLIENT_BAL_DUE_C1

Explain the relational completeness, Explain the Relational Completeness ...

Explain the Relational Completeness Codd described the term relational completeness to consider to a language that is complete with respect to first-order predicate calculus ex

Explain the 10 reasons to use mysql, Question 1 Explain the 10 reasons to ...

Question 1 Explain the 10 reasons to use MySQL Question 2 Write the SQL statements to demonstrate the following using SELECT command Expression Evaluation ORDER BY

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