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

Remove all transitive dependencies - dependency diagram, 1. Use the Invoice...

1. Use the Invoice table structure shown below to answer the following questions: a)  Draw the dependency diagram and identify the primary key and all dependencies, including al

What is the difference between serial and sequential files, What is the dif...

What is the difference between serial and sequential files? How searching is applied on both?    Ans: A serial file is one where the records have been stored in the order where

Working and processing files, 1.  Define each of the following IN YOUR OWN ...

1.  Define each of the following IN YOUR OWN WORDS: (a)   File: (b)   Record: (c)   Field: (d)   Primary Key: (e)   Secondary Key: 2.  A travel agency wants t

Cartisian product, Explain the cartesian product in Database Management Sys...

Explain the cartesian product in Database Management System

What are called jukebox systems, What are called jukebox systems? Jukeb...

What are called jukebox systems? Jukebox systems have a few drives and numerous disks that can be loaded into single of the drives automatically.

Explain in detail about collaboration diagrams, Explain in detail about Col...

Explain in detail about Collaboration Diagrams Collaboration diagrams are interaction diagrams which emphasize structural organisation of an object that transmit and receive m

Data base design, how to design a bakery business in data base

how to design a bakery business in data base

Data warehouse, 1) Define a job scheduling strategy that will meet business...

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

What is vertical fragmentation, What is vertical fragmentation? Vertica...

What is vertical fragmentation? Vertical fragmentation divides the relation by decomposing the scheme R of relation 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