Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Failures and Recovery
In practice various things might occur to prevent a transaction from completing. Recovery methods are used to bring database, which does not satisfy consistency needs, into a consistent state. If a transaction finishes normally and commits then all the alters made by the transaction on the database are permanently registered in the database. They should not be lost. But, if a transaction does not finish normally and terminates abnormally then all the changes made by it should be discarded. An abnormal termination of a transaction may be because of various causes, including:
a) User may decide to terminate the transaction issued by him/ her
b) There may be a deadlock in the system
c) There may be a system failure.
The recovery mechanisms must make sure that a consistent state of database can be restored under all circumstances. In case of transaction terminate or deadlock, the system remains in control and can deal with the failure but in case of a system failure the system loses control because the computer itself has failed. Will the results of such type of failure be catastrophic? A database has a vast amount of useful information and any system failure should be recognised on the restart of the system. The DBMS should recover from some such failures.
Example :; transfers transfer_amount from x's account to y's account ; Supposes x&y both accounts exist TRANSACTION (x, y, transfer_amount) Start transaction IF X AND Y
The users who use easy-to-use menu are called ? The users who use easy to use menu are called as Naïve users.
Describe the storage structure of indexed sequential files and their access method. Ans: Storage structure of Indexed Sequential files and their access: To achieve fast rand
Differentiate between B-tree and B + tree Ans: A B-tree (or Balanced Tree) is a search tree along with additional constraints that makes sure that the tree is all the time
Using Literal Character String Example: To print IS A as one string with column name employee SELECT ENAME || ' IS A ' || JOB AS "EMPLOYEE" FROM EMP;
What is the error handling Traditionally, bits have been sent over line lacking any error correcting scheme in physical layer. The presence of the CPU in each modem makes it po
Project Description: I need a point of sale for motels. It needs to run on windows and requires being network able so that we can have more than one computer using it at once.
Determine the OBJECTIVES of object design After passing through this unit, you should be able to: describe and apply concept of generalisation; understand and appl
Evaluate, compare and contrast the two methods of relational database design namely top down method and Bottom up method. What will be your choice if you are asked to select a meth
Record based Logical Models: Use records as the key data representation components Examples: Relational Model: It shows data as well as relationship between data in the form
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd