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.
A constraint named less_than_20 was defined on the field date_of_birth of table student. Delete this constraint. ALTER TABLE student DROP CONSTRAINT less_than_20;
Let consider the given partial relation EMP. Let us make some sub-queries for them EMPNO ENAME JOB SAL DEPTNO 7566
external and internal mapping with examples
What is Data dictionary? A data dictionary is a reserved space in a database that is employed to store information about the database itself. A data dictionary may consist o
Prove that a relation which is 4NF must be BCNF. Ans Let R be in 4NF. Suppose it is not in BCNF. Hence, there exists an FD X→Y in R such that x is not a super key. Although
What is Information System?
Define Cascading rollback The phenomenon where a single transaction failure leads to a series of transaction rollbacks is known as Cascading rollback.
#question. acompani datdbase needs to store information about employees (identified by a social security number,with salary and phone as attributes) and departments (identified by
What is data integrity? Ans: It is the data consisted of in database that is accurate and consistent. (Data integrity means that the data should be valid as per to the give
1. Which relational algebra operations do not need the participating tables to be union-compatible? Ans: Join is the relational algebra operations that do not need the particip
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