Explain mechanism of nested queries, Database Management System

Assignment Help:

Explain mechanism of nested queries?

SQL gives a mechanism for nesting subqueries. A subquery is a select from where expression that is nested within one more query. A common use of sub queries is to perform tests for set membership, make set comparisons, and verify set cardinality.

a) Set membership

(select customer-name

from depositor)

b) Set comparison

select distinct T.branch-name

from branch as T,branch as S

where T.assets > S.assets and S.branch-city='Brooklyn'

a) Test for Empty Relations

Select customer-name

from borrower

where exits (select *

from depositor

where depositor.customername=borrower.customer-name)

a) Test for the Absence of Duplicate Tuples

 

 


Related Discussions:- Explain mechanism of nested queries

Designing the hierarchy of a ldb?, What sorts of tables one can se in desig...

What sorts of tables one can se in designing the hierarchy of a LDB? Tables, which are having Foreign Key relations.

What are the different integrity constraints in rdbms, What are the differe...

What are the different integrity constraints in RDBMS? The various integrity constraints in RDBMS are as: Primary Key: primary key is a grouping of one or more attributes

List the set operations of sql, List the set operations of SQL? 1) Unio...

List the set operations of SQL? 1) Union 2) Intersect operation 3) The except operation

Physical location of record is determined by which formula, The physical lo...

The physical location of a record is determined by which mathematical formula that transforms a file key into a record location? The physical location of a record is determined

Applications and goals of dbms, What do you mean by DBMS? What is its need ...

What do you mean by DBMS? What is its need and what are its goals. Explain?        OR   Explain Data Base Management System? Sol.  Database management system is a

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

what is RDBMS? how it works? good example.

Describe data manipulation language, Describe Data Manipulation language ? ...

Describe Data Manipulation language ? Data Manipulation Language (DML) - A data manipulation language is a language which enables users to access or manipulate data as organize

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