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!
Strict 2PL:Though, this basic 2PL suffers from the trouble that it can result into loss of isolation / atomic property of transaction as theoretically speaking once a lock is released on a data item it can be changed by another transaction before the first transaction aborts or commits.
To leave such a situation we use strict two phase locking. The strict 2PL is graphically depicted in Figure. Though, the basic drawbacks of strict 2PL are that it restricts concurrency as it locks the item afar the time it is required by a transaction.
Figure: Strict Two Phase Locking
Does the two phase locking solve all the problems of concurrent transactions? No, the strict 2PL answers the problem of concurrency and atomicity, though it introduces another problem.
These are interactive interfaces, graphical that hide the difficulty of the DBMS and query language behind an intuitive, simple to understand, and convenient interface. This permit
What is the use of unique function? UNIQUE function: If UNIQUE is specified then only unique values are used to computed the mean.
Define the concept of aggregation. Give two examples where this concept is useful. Ans: Aggregation transforms a relationship among the objects into a higher-level object. A
Define query language? A query is a statement requesting the retrieval of information. The portion of DML that includes information retrieval is known as a query language.
Suppose that in an organisation, an employee may do different roles in dissimilar projects. Say, RAM is doing coding in one project and doing designing in another. Suppose that the
Boyce-Code Normal Form (BCNF) A relationship is said to be in BCNF if it is already in 3NF and the left hand side of each dependency is a candidate key. A relation who is in 3N
Give the two reasons for allowing concurrency
In a relational model how relations are termed? In a relational model, relations are termed as tables. (The term ‘relation’ is the technical name of the ‘table’ in RDBMS)
Consider the ER schema below for the MoneyMaking supermarket chain problem. Translate the given ER schema into SQL CREATE TABLE statement.
A table joined with itself is called ? A table joined with itself is known as self join table. Normal 0 false false false EN-IN X-NONE X-NONE
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: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd