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!
A distributed transaction consists of subtransactions that execute at different sites and access local DBMSs at those sites. For example, a distributed transaction that transfers money from a bank account at site A to a bank account at site B executes a subtransaction at A that does the withdrawal and then a subtransaction at B that does the deposit.
Such a distributed transaction must satisfy the ACID properties in a global sense: it must be globally atomic, isolated, consistent, and durable. The issue is, if the subtransactions at each site individually satisfy the ACID properties, does the distributed transaction necessarily satisfy the ACID properties? Certainly if the subtransactions at each site are individually durable, the distributed transaction is durable. Give examples of situations in which
(a) The subtransactions at each site are atomic, but the distributed transaction is not atomic.
(b) The subtransactions at each site are consistent, but the distributed transaction is not consistent.
(c) The subtransactions at each site are isolated, but the distributed transaction is not isolated.
Write the motivations led to development of OO-DBMS? 1. Programmer frustration with RDBMSs. 2. Requirement for special features.
BCNF Boyce-Codd Normal Form A relation schema R is in BCNF if it is in 3NF and accepts an additional constraint that for every FD X A, X has to be a candidate key. If a relati
In an E-R diagram an entity set is represent by? In an E-R digram entity set is represted by rectangle.
An instance of relational schema R (A, B, C) has distinct values of A including NULL values. then A is a candidate key or not? If relational schema R (A, B, C) has distinct val
Describe the Composite Key Composite Key: Sometimes one key is not enough to uniquely recognize a row. E.g. in a single class Roll is enough to search a student, but in the w
wh
What is known as heap file organization? In the heap file organization, any record can be placed anywhere in the file where there is space for the record. There is no ordering
Describe the algorithm for updating indices for a single level index when a record is (i) Inserted (ii) deleted What will be the modification if there are multilevel in
What are the purpose for having variable length records? What kinds of separator characters are required for each? Variable-Length Records - Variable-length records are thos
Explain the Management of Data Store Every system irrespective of its nature of application requires storing permanent data for consequent use in problem solving. Some objects
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