Vertical fragmentation, Database Management System

Assignment Help:

Vertical Fragmentation-Vertical fragmentation groups together only those attributes in a relation that are used jointly by various important transactions. A vertical fragment is described using the Projection operation of the relational algebra. In its most easy form, vertical fragmentation is the similar as that of decomposition. In common, a relation can be constructed on taking Natural join of all vertical fragments.

More usually, vertical fragmentation is accomplished by adding a special attribute known as a tuple-number to the scheme R. A tuple-number is a logical or physical address for a tuple. Therefore every tuple in R must have a unique address, the tuple- number attribute is a key to the new fragments get (please refer to Figure ).

Branch-code

Account number

Customer name

Balance

Tuple-number

1101

3050

Suresh

5000

1

1101

2260

Swami

3360

2

1102

1170

Swami

2050

3

1102

4020

Khan

10000

4

1101

1550

Khan

620

5

1102

4080

Khan

1123

6

1102

6390

Khan

7500

7

                                      Figure: The relation DEPOSIT of figure 5 with tuple- numbers

This  relation  now  can  be  decayed  into  two  fragments  as:  demonstrates  a  vertical decomposition of the scheme Deposit-scheme tuple number into:

DEPOSIT3 = ∏  (branch-code. customer-name, tuple-number) (DEPOSIT)

DEPOSIT4 = ∏  (account-number, balance, tuple-number) (DEPOSIT)

The example of above Figure on this basis would become:

DEPOSIT3

Branch-code

Customer-name

Tuple-number

1101

Suresh

1

1101

Swami

2

1102

Swami

3

1102

Khan

4

1101

Khan

5

1102

Khan

6

1102

Khan

7

DEPOSIT4

Account number

Balance

Tuple-number

3050

5000

1

2260

3360

2

1170

2050

3

4020

10000

4

1550

620

5

4080

1123

6

6390

7500

7

                                                     Figure: Vertical fragmentation of relation DEPOSIT

How can we rebuild the original relation from these 2 fragments? By taking natural join of the 2 vertical fragments on tuple-number. The tuple number permits direct retrieval of the tuples without the required for an index. Therefore, this natural join may be computed much extra efficiently than typical natural join.Though, please note that as the tuple numbers are system generated, thus they should not be visible to common users. If users are given access to tuple-number, it happens to impossible for the system to change tuple addresses.

 


Related Discussions:- Vertical fragmentation

Decomposition properteis, what is lossless & dependency preserving decompo...

what is lossless & dependency preserving decomposition ?

Explain concept of inheritance with support of example, Explain concept of ...

Explain concept of inheritance with support of suitable example. Inheritance Inheritance is one of milestone of object-oriented programming language as it allows a creati

Functional dependencies, 1. Staff (staffID --> availabilityID) 2. Servic...

1. Staff (staffID --> availabilityID) 2. Services (servicesID --> itemBasedID --> timedBasedID) 3. TimedBased (timedbasedID--> priceid) 4. Clients (clientId, serviceId-->

Explain the exists and unique functions of sql, Explain the EXISTS and UNIQ...

Explain the EXISTS and UNIQUE functions of SQL. Give an example for each? EXISTS: The EXISTS function takes one parameter that is a SQL statement. If any records exist which

Explain the data access protocol, (a) Explain the three types of potentia...

(a) Explain the three types of potential mistake which could occur if concurrency control is not properly enforced in the database system. Support your answer with appropriate ex

Union - basic set operation, UNION If R1 and R2 are two union compatibl...

UNION If R1 and R2 are two union compatible relations then R3 = R1 ∪ R2 is the relation having tuples that are either in R1 or in R2 or in both. In case, R3 will have tuples

Please answer me., gyan gurukul is a software company that provides softwar...

gyan gurukul is a software company that provides software related solution.

What is data defination language, What is DDL? Make a list of commands with...

What is DDL? Make a list of commands with short description used in DDL Ans: Data Definition Language that is abbreviated as DDL is a computer language for defining data struct

Explain different addressing modes of 8086, 1. Explain different addressing...

1. Explain different addressing modes of 8086 Explanation of all addressing modes 2. Write a sequence of instructions to exchange two register contents using stack

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