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!
"Wound-wait" scheme: It is based on a preemptive method. It is based on a simple rule:
If Ti requests a database resource that is held by Tj
then if Ti has a larger timestamp (Ti is younger) than that of Tj
it is allowed to wait;
else Tj is wounded up by Ti.
For example, suppose that 3 transactions T1, T2 and T3 were generated in that series, then if T1requests for a data item which is presently held by transaction T2, then T2 is rolled back and data item is allotted to T1 as T1 has a smaller time stamping than that of T2. Though, if T3 requests for a data item which is presently held by transaction T2, then T3 is permitted to wait.
Figure: Wound-wait Scheme of Deadlock prevention
It is vital to see that whenever any transaction is rolled back, it would not make a starvation condition, i.e., no transaction gets rolled back repeatedly and is never permitted to make progress. Also both "wait-die" & "wound-wait" idea avoid starvation. The number of aborts & rollbacks will be higher in wait-die scheme than in the wound-wait idea. But one main problem with both of these ideas is that these ideas may result in unnecessary rollbacks.
What are the technique to define a schema completely ? A schema is completely define by DDL and DML query language.
The PROJECT operation The project operation is used to choose the records with specified attributes as discarding the others based on some related criteria. This is denotes as ∏
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
Define functional and multivalued dependencies. Ans: A functional dependency is a assets of the semantics of the attributes in a relation. The semantics point out how at
Discuss deferred update technique of recovery. What are the advantages? Ans: The deferred update methods do not physically update the database on disk till after a transact
Explain Object oriented Model ? Object Oriented Model - This model is based on the object-oriented programming language paradigm. It involves the features of OOP such as inhe
statical data
What are domain constraints? A domain is a set of values that might be assigned to an attribute .all values that appear in a column of a relation must be taken fro
What is a security? Securities are claims on financial assets. They can be illustrated as "claim checks" which give their owners the right to receive funds in the future. Sec
What are the two distinct aspects to the implementation of associations? i) It is required to define data declarations which will enable details of actual links to be stored. I
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