Dirty reads-problems of concurrent transactions, Database Management System

Assignment Help:

Dirty Reads: T10 reads a value which is updated by T9. This update has not been committed and T9 aborts.

T9

T10

Value of x old value =

200

T9

T10

UPDATE X

 

500

 

 

READ X

 

500

ROLLBACK

 

200

?

Here T10 reads a value that is updated by transaction T9 that has been aborted. Therefore T10 has read a value that would never exist in the database and hence the trouble. Here the difficulty is primarily of isolation of transaction.

 


Related Discussions:- Dirty reads-problems of concurrent transactions

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

Access data using logical database, If one requires to access data using...

If one requires to access data using Logical Database , the use of events is unavoidable. Yes, if someone wants to access data using Logical database then the use of events

Which is a legal expression in sql, Which is a legal expression in SQL? ...

Which is a legal expression in SQL? SELECT NAME FROM EMPLOYEE is a legal expression in SQL.

Define partial key and primary key, Define Partial Key and Primary Key ...

Define Partial Key and Primary Key A partial key, also known as discriminator, is the set of attributes which can uniquely identify weak entities that are related to similar o

Draw an erd for the above relational schema, The following relational datab...

The following relational database schema represents part of a simplified database used by a library: tblBook (BookID, Title, PublisherID, Category,Price) tblPublisher (Publishe

Keys - relational database integrity, Candidate Key:  In a relation R, a ca...

Candidate Key:  In a relation R, a candidate key for R is a subset of the set of attributes of R, which have the differnt two properties: (1)        Uniqueness:                N

Project, I need help in doing my dbms project

I need help in doing my dbms project

How to apply the bcnf decomposition , Consider the following relational sch...

Consider the following relational scheme: R (a,b,c,d,e,f) and its corresponding set of FDs {d→ a, be → c, ac → e, b → f, f → d, a → c}. a. Is the following decomposition i) non

Describe integrity constraints, Describe integrity constraints? Integr...

Describe integrity constraints? Integrity Constraints - A database is just as excellent as the information stored in it, and a DBMS must therefore help avoid the entry of inc

Cascading, what is cascading? what is rollback cascading? please explain in...

what is cascading? what is rollback cascading? please explain in detail

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