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

CMIS 420 Homework Assignment 2, describe all the tables you have created. ...

describe all the tables you have created. ?get table_name, status, num_rows, user_stats in user_tables system view ?get table_name, constraint_name, constraint_type in user_constr

What is management system, What is Management System? A management syst...

What is Management System? A management system is a set of rules and process which help us to create organize and manipulate the database. It also helps us to add, change delet

What is database trigger, What is database Trigger? A database trigger ...

What is database Trigger? A database trigger is a PL/SQL block that can explained to automatically execute for insert, update, and delete statements against a table. The trigge

Alter table command, ALTER TABLE Command : This command is used for variati...

ALTER TABLE Command : This command is used for variation of existing structure of the table in the given situation: When a new column is to be added to the table structure.

How the one-to-one associations have to be implemented, Discuss how the one...

Discuss how the one-to-one associations have to be implemented. Some of properties of associations can be implemented directly by providing suitable declarations of the data me

Express types of information available in mysql, Express types of informati...

Express types of information available in MySQL? Information as regards the result of queries:  This includes number of records affected by any SELECT or UPDATE or DELETE st

What do you mean by an execution plan, What do you mean by an execution pla...

What do you mean by an execution plan? Why is it used? How will you view it? a.) An execution plan can be known as a road map which textually or graphically illustrates the dat

Define the wait for graph, Define the Wait for graph Ans: The wait-for-...

Define the Wait for graph Ans: The wait-for-graph is a directed graph and consist of nodes and directed arcs; the nodes of the graph are active transactions. An arc of the grap

Describe the nested-loop join and block-nested loop join, Describe the nest...

Describe the nested-loop join and block-nested loop join.   Ans:   The block nested- loop join algorithm is as described below:     for every block B r of relation R do beg

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