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

Define hot backup, Hot Backup: Some sites cannot terminate the database wh...

Hot Backup: Some sites cannot terminate the database while creating a backup copy of the files. The cold backup is not a reliable option. So different kinds of backing up database

Dbms, Retrieve the S&S In-Chapter Database (in Microsoft Access format) fro...

Retrieve the S&S In-Chapter Database (in Microsoft Access format) from the text's Web site (or create the tables in Table 4-5 in a relational DBMS product). Write queries to answer

find a non-redundant cover and canonical cove, Given the following set of ...

Given the following set of functional dependencies {cf→ bg, g → d, cdg → f, b → de, d → c} defined on R(b,c,d,e,f,g) a. Is cf→ e implied by the FDs? b. Is dg a superkey?

Structure of the ldb, Though all the ABAP/4 Dictionary Structures that exis...

Though all the ABAP/4 Dictionary Structures that exists in the structure of the LDB, being described in Database Program, we are explaining the Dictionary Structures in the Report.

Execute sql queries, Consider the relations described below: PHYSICIAN (re...

Consider the relations described below: PHYSICIAN (regno, name, telno, city) PATIENT (pname, street, city) VISIT (pname, regno, date_of_visit, fee) Where the regno and pname ide

Original Database, I need an ERD created for any original database(can be o...

I need an ERD created for any original database(can be on anything). It needs to be 3NF. I then need all the CREATE STATEMENTS, INSERT STATEMENTS(anything you can think of as long

Decompose the table with the functional dependencies, Decompose the table w...

Decompose the table with the following description and functional dependencies into a set of equivalent tables normalized to 3NF or BCNF. This database stores records from a (ve

Illustrate the collaboration and relationship diagram, Illustrate the colla...

Illustrate the collaboration and relationship diagram A collaboration is the society of interfaces, classes and other elements which work together to provide some cooperative b

Example of weak entity, Consider the entity type dependent related to emplo...

Consider the entity type dependent related to employee entity, which is used to keep track of the dependents of every employee. The attributes of dependents are: name, sex, birth d

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