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

Using literal character string-data manipulation language, Using Literal Ch...

Using Literal Character String Example: To print IS A as one string with column name employee SELECT ENAME || ' IS A ' || JOB AS "EMPLOYEE" FROM EMP;

What are the various properties of relational tables, What are the various ...

What are the various properties of Relational tables? Relational tables have 6 properties: 1. Each row is unique. 2. Column values are of the same kind. 3. Values are

Back up files, what is the importance of back up files

what is the importance of back up files

Explain different types of keys and relational model., Relational Model: T...

Relational Model: The relational model uses a collection of tables to represent both data and the relationships among those data. Each table has multiple columns and each column h

Creating views with check option-data control, Creating views with check op...

Creating views with check option : This option limits those updates of data values that cause records to go off the view. The following instance tells this in more detail: Examp

What is system log, What is system log?  What are the entries?       An...

What is system log?  What are the entries?       Ans:  The system log that is generally written on stable storage contains the redundant data required to recover from volatile

Explain the weak entity set, Explain the Weak Entity Set An Entity set...

Explain the Weak Entity Set An Entity set which does not have sufficient attribute to make a primay key is known as weak entity set. For instance, dependents of an employee in

A Biological Database on Viruses, How to create a biological database based...

How to create a biological database based on viruses. How to decide which attribute should be there in the table and schema? How to identify the primary keys, foreign keys, domain,

Project, I need help in doing my dbms project

I need help in doing my dbms project

What are the properties in a relation, What are the properties in a relatio...

What are the properties in a relation ? In a relation Ordering of rows is immaterial and No two rows are identical.

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