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 dbms and what are functions of dbms, What is DBMS and what are func...

What is DBMS and what are functions of DBMS? DBMS consist of collection of integrated data and set of program to admission those data. The functions performed by a typical

The logical dbms architecture, Normal 0 false false false ...

Normal 0 false false false EN-IN X-NONE X-NONE

Explain interblock gap, Explain Interblock gap? Interblock Gap - A trac...

Explain Interblock gap? Interblock Gap - A track of a disk is separated into equal-sized disk blocks. Blocks are separated through fixed-size gaps, called as interblock gaps th

Describe participation constraints, Describe Participation Constraints? ...

Describe Participation Constraints? Participation Constraints - The participation constraint exacts whether the existence of an entity depends on its being related to another

Identify all renters who have viewed all properties, Consider the subsequen...

Consider the subsequent relations RENTER(rno, fname, lname, address, tel_no, pref_type, max_rent) VIEWING(rno, pno, date, comment) PROPERTY_FOR_RENT( pno, street, area ,city,

Dataset, The dataset " CFOLYMPICS.XLS " contains the observations used in t...

The dataset " CFOLYMPICS.XLS " contains the observations used in the above article.  The definitions of the variables are also included in this spreadsheet.  However, for the purpo

Data replication, Data Replication "If a relation R has its copies kept...

Data Replication "If a relation R has its copies kept at two or more sites, then it is considered replicated". But why do we replicate a relation? There are several advan

Seeking hr searcher, Project Description: The work is about founding the...

Project Description: The work is about founding the best skilled person for the job. I will give you the job description. Skills required are Data Entry, Database Administrat

Determine the term- active values, Determine the term- Active values An...

Determine the term- Active values An active value is that has dependent values. Every dependent value registers itself with active value that contains a set of dependent values

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