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

OLAP CUBES, 1) Define a job scheduling strategy that will meet business req...

1) Define a job scheduling strategy that will meet business requirement of reporting availability by 6am CST for the following cubes? Show the job scheduling dependencies in a pict

Attributes and tuple, Before we talk about the relational model in more det...

Before we talk about the relational model in more detail, let us first define some very basic terms used in this model. Tuple Every row in a table shows a record and is cal

Define the five basic operators of relational algebra, Define the five basi...

Define the five basic operators of relational algebra? Five basic operators of relational algebra are: 1. Union (∪∪∪∪) - Selects tuples which are in either P or Q or in both

Explain the advantages of dbms over file oriented system, Explain the main ...

Explain the main advantages of DBMS over File Oriented System ?

Aims of the design project, The aims of the project are: 1. To enable th...

The aims of the project are: 1. To enable the students to undertake the detailed design of a specific plant or process 2. The design projects includes: process selection; und

What are the drawbacks of shadow-paging technique, What are the drawbacks o...

What are the drawbacks of shadow-paging technique? The drawbacks of shadow paging is:- a) Commit Overhead b) Data fragmentation c)  Garbage collection

In an e-r diagram how attributes are represented, In an E-R diagram how att...

In an E-R diagram how attributes are represented ? In an E-R diagram attributes are represented in a ellipse.

Define two-phase locking protocol, Define two-phase locking protocol. A...

Define two-phase locking protocol. Ans: Two-phase locking is significance in the context of ensuring that schedules are serializable. The two-phase locking protocol defines a p

What are the advantages of logical databases, What are the advantages of Lo...

What are the advantages of Logical Databases? It offers a simple-to-use selection screens.  You can change the pre-generated selection screen to your needs.  It offers check f

Explain query execution plan, Explain query execution plan? - Optimizer...

Explain query execution plan? - Optimizer available in SQL Server optimizes code to be effectively executed. - A query execution plan demonstrates how this optimizer would r

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