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

Order by clause-data manipulation language, Order by clause By usin...

Order by clause By using this rows can be sorted It is used in the last portion of select statement By default it gets ascending order DESC: is used

Apriori algorithm-find all frequent large itemsets, Your friend owns a comp...

Your friend owns a computer store in Yuen Long, selling Desktop and Notebook PCs and other computer peripherals. Having been rather successful with his business there, he decided t

What is data mining?, Question 1 Define OLTP? Explain the Differences betw...

Question 1 Define OLTP? Explain the Differences between OLTP and Data Warehouse Question 2 What is Architecture? Explain various components involved in it Question

The external or view level in dbms, The External or View Level The ex...

The External or View Level The external or view level is the highest level of abstraction of database. It gives a window on the conceptual view, which permits the user to see

aggregate functions-data manipulation language, Aggregate functions ...

Aggregate functions Some of these functions are min, count, max, and avg. These functions help in getting consolidated information from a set of tuples. Example:

Write the sql code, Express the following queries in SQL: (a) Write the...

Express the following queries in SQL: (a) Write the SQL code that will create ALL the four tables given in the appendix. Your answer should not contain the primary key and

What is a records management consultation, What is a records management con...

What is a records management consultation? Our organization is an authority for disseminating your specific requirements and giving you with a solution to effectively manage yo

List the requirements needed to design a trigger, List the requirements nee...

List the requirements needed to design a trigger. The requirements are:- Specifying when a trigger is to be implemented. State the actions to be taken when the trigger im

Isolation or independence-transaction , Isolation or Independence : The iso...

Isolation or Independence : The isolation property shows that the updates of a transaction should not be visible till they are committed. Isolation assurance that the progresses of

What is conceptual model, What is conceptual model ? A conceptual model...

What is conceptual model ? A conceptual model is a independent of both hardware and software.

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