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!
The Concurrent Transactions
Almost every commercial DBMS support multi-user environment. Therefore, allowing multiple transactions to proceed concurrently. The DBMS must make sure that two or more transactions do not obtain into each other's way, i.e., transaction of one user doesn't effect the transaction of other or even the transactions issued by the similar user should not get into the way of each other. Be advised that concurrency related problem may happen in databases only if two transactions are contending for the similar data item and at least one of the concurrent transactions wishes to update a data value in the database. In this, the concurrent transactions only read similar data item and no updates are done on these values, then it does NOT create any concurrency related difficulty. Now, let us talk about why you require a mechanism to control concurrency.
Consider a banking application dealing with saving and checking accounts. A Banking Transaction T1 for Mr. Sharma moves Rs.100 from his checking account balance X to his savings account balance Y, using the transaction T1:
Transaction T1:
A: Read X
Subtract 100
Write X
B: Read Y
Add 100
Write Y
Let us assume an auditor wants to know the total assets of Mr. Sharma. He implements the following transaction:
Transaction T2:
Read X Read
Y Display
X+Y
Assume both of these transactions are issued concurrently, and then the implement of these instructions can be combined in many ways. This is also known as the Schedule. Let us describe this term in more detail.
A schedule S is described as the sequential ordering of the operations of the 'n' interleaved transactions. A schedule keeps the order of operations within the individual transaction.
One possible schedule for interleaved execution of TA and TB
What do you mean by persistence? How you will make your data persistent? Persistent data is the data, which has a longer lifetime than program which has created it. Enabling th
What are the three data anomalies that are likely to occur as a result of data redundancy? Can data redundancy be completely eliminated in database approach? Why or why not? A
What is inheritance? Inheritance is an object orientation concept that allows reusability of code / design. Basic sense of inheritance is that if one class is predefined than a
difference between internal schema and external schema in DBMS
Project Description: Looking to prepare automated trading engine for alternate cyprto currencies starting with Cryptsy, finally integrating into other exchanges. Need to work wi
By using the delete operation some consisting records can be deleted from a relation. To delete some definite records from the database a condition is also specified based on which
a. Construct a query around any one of the functional divisions you made in 4a such that if executed in the distributed design of 4 would require reconstruction of at least two ho
Analyzing Association Traversal Till now, we have supposed that associations are bi-directional. But in the case of traversal, it is in only one direction in any application,
Explain cursors in SQL? Cursors in SQL - An object used to store the output of a query for row-through-row processing through the application programs. Cursors are constructs
What is a function group? A function group is a collection of logically related modules that share global data with every other. All the modules in the group are contained in
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