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

Explain trivial dependency, Explain trivial dependency? Functional depe...

Explain trivial dependency? Functional dependency of the form α ->β. is trivial if α C β. Trivial functional dependencies are satisfied by all the relations.

In an e-r diagram an entity set is represent by, In an E-R diagram an entit...

In an E-R diagram an entity set is represent by? In an E-R digram entity set is represted by rectangle.

What are the four main characteristics of the database, What are the four m...

What are the four main characteristics of the database approach? The four major characteristics of the database approach are: 1. Self-describing nature of a database system. 2.

RDBMS, what is RDBMS? how it works? good example.

what is RDBMS? how it works? good example.

Explain physical and logical independence, Define Physical and Logical inde...

Define Physical and Logical independence  Ans: Physical data independence: The ability to modify physical level without causing application program to be rewritten. Logic

#cursor, #what is cursor its uses ? Explain it

#what is cursor its uses ? Explain it

How is oracle used in pl/sql, How is Oracle used in PL/SQL? Define the feat...

How is Oracle used in PL/SQL? Define the features of process and how they are defined? PL/SQL - PL/SQL is Oracle's procedural language (PL) superset of the Structured

Tuples-attributes , Consider a relation s over the attributes A and B wit...

Consider a relation s over the attributes A and B with the following characteristics: 5,000 tuples with 10 tuples per page A 2-level B+ tree index on attribute

Graphical user interface tools, These are interactive interfaces, graphical...

These are interactive interfaces, graphical that hide the difficulty of the DBMS and query language behind an intuitive, simple to understand, and convenient interface. This permit

Explain embedding sql statements, Question 1 Explain the functions of t...

Question 1 Explain the functions of the following Storage Manager Buffer Manager Transaction Manager 2 Discuss about system catalog in a relational DBMS 3

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