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!
Serialisable Schedules:If the processes of two transactions conflict with each other, how to verify that no concurrency related problems have happened? For this, serialisability theory has been developed. Serialisability theory attempts to verify the correctness of the schedules. The rule of this theory is:
"A schedule S of n transactions is serialisable if it is equal to some serial schedule of the similar 'n' transactions".
A serial schedule is a schedule in which either transaction T1 is totally done before T2 or transaction T2 is totally done before T1. For instance, the following figure clears the two possible serial schedules of transactions T1 & T2.
Schedule A: T2 followed by T1
Schedule B: T1 followed by T2
Schedule
T1
T2
Read X
Read Y
Subtract 100
Display X+Y
Write X
Add 100
Write Y
Figure: Serial Schedule of two transactions
Schedule C: An Interleaved Schedule
Figure: An Interleaved Schedule
Now, we have to figure out whether this interleaved schedule would be performing read and write in the same order as that of a serial schedule. If it does, then it is equivalent to a serial schedule, otherwise not. In case it is not equivalent to a serial schedule, then it may result in problems due to concurrent transactions.
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 consi
Define deadlock avoidance. An alternative method for avoiding deadlocks is to needs additional information about how resources are to be requested. Each request requires the s
We are looking to find someone to prepare a database which improves upon the one we are using at present. The present database will be found here: Click on filter options and yo
What are wait-for-graphs?Give the algorithm to construct a wait-for-graph from a given schedule of transactions? How can deadlocks be detected from wait-for-graphs? Ans: The
Copy Data from One Database to another Database Project Description: I am having two MySQL databases with same tables. I just need to copy one Data from one to another dat
What is storage manager? A storage manager is a program module that gives the interface between the Low level data kept in a database and the application programs
Security: In a centralised system, access to the data can be simply controlled. Though, in a distributed DBMS not only does access to replicated data have to be controlled in many
Explain the ISA relationship Answer: ISA relationship - ISA notation is employed in generalization/ specialization to depict relationship among lower and higer level entity s
What is the difference between a key and a superkey? Key - A key a single attribute or a combination of two or more attributes of an entity set which is used to identify one
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,
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