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.
Explain Hashing techniques The hashing techniques can be categorized as: Static Hashing Techniques - In this method, the data can be viewed a collection of buckets, along with
In the ER diagram, one example of subclassing is depicted following the Services entity. The subclasses Item Based and Time Based are created. The entity Services gains the attribu
Describe Query evaluation engine? Query Evaluation engine: Vehicle executes low-level instructions obtained through the DML compiler. The Storage Manager Components gives in
A step-wise distributed database design methodology Following is a step-wise methodology for distributed database design. (1) Examine the nature of distribution. Find out wh
Differance between internal and external schema? Internal and external schema: Internal Schema • Describes the physical storage structure • Uses a physical data model External
sir, could anybody help me in getting complete information about the mentioned topic
Briefly explain the state diagram by taking one example. State Diagram - An object can be given a sequence of input instructions. The state of the object can vary depending u
Describe analysis of access paths To describe analysis of access paths, consider an example of the design of a company's employee skills database. A part of the object model fr
Log based recovery: Let us first describe the term transaction log in the context of DBMS. A transaction log is a record in DBMS that remains track of all the transactions of a dat
external and internal mapping with examples
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