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.
Data Warehousing & Mining 1. What is the concept of knowledge discovery in database? 2. Describe the following types of Multidimensional Data Models. • Stars, Snowflakes and
Explain the difference between using functions along with and without grouping attributes in relational algebra. Give examples. Ans: Group functions are used to group data of
Birla Institute of Technology & Science, Pilani Work-Integrated Learning Programmes Division Second Semester 2012-2013 EC-1 Assignment 2 (7.5% of the grade) Course No. : SS ZG
Express types of information available in MySQL? Information as regards the result of queries: This includes number of records affected by any SELECT or UPDATE or DELETE st
it can be possible to create any table without primary key
Project Description: We have an encrypted HSQL Database which we want to change into csv format. HSQL DB . We have java application (jar file) which reads that database but n
Define rotational latency time. The time spent waiting for the sector to be accessed to appear under the head is known as the rotational latency time.
Consider the relations EMPLOYEE(emp#, name) ASSIGNED_TO(project#, emp#) PROJECT(project#, project_name, chief) Express the subsequent queries in Relational Algebra (i) Ge
Using Relational Algebra which query finds customers, who have a balance of over 1000 ? Using Relational Algebra Π Customer_name( σ balance >1000(Deposit)) is query to find cu
Give a sample of the Dynamic Model. The sample of dynamic model is given below: Dynamic model for the car: Brake and Accelerator Brake or Applies Accelerator
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