The locking protocol, Database Management System

The Locking Protocol: To manage concurrency related problems we use locking. A lock is mainly a variable that is associated with a data item in the database. A lock can be located by a transaction on a shared resource that it needs to use. When this is completed, the data item is available for the exclusive use for that transaction that is other transactions are locked out of that data item. When the transaction that has locked a data item does not need to use it any longer, it should unlock the data item so that other transactions can use it. If a transaction attempts to lock a data item already locked by some other transaction, it cannot do so and remains for the data item to be unlocked. The parts of DBMS that controls and stores lock information is known as the Lock Manager. The locking mechanism helps us to change a schedule into a serialisable schedule. We had definite what a schedule is, but what serialisable schedule is?

 

Posted Date: 3/12/2013 1:53:06 AM | Location : United States







Related Discussions:- The locking protocol, Assignment Help, Ask Question on The locking protocol, Get Answer, Expert's Help, The locking protocol Discussions

Write discussion on The locking protocol
Your posts are moderated
Related Questions
The users who use easy-to-use menu are called ? The users who use easy to use menu are called as Naïve users.

Write short notes on domain relational calculus The domain relational calculus uses domain variables that take on values from an attribute domain rather than values for whole t

Define the following constraints for the table client. (i) BAL_DUE must be at least 1000. (ii) NAME is a unique key. (i)ALTER TABLE CLIENT ADD CONSTRAINT CLIENT_BAL_DUE_C1

Desirable Properties Of Decomposition Decomposition is a process of dividing a relation into its projections that will not be disjoint. Please remind the Relational projection

The Maximum no of key fields that can be used in a header is?? 50

What is Asterisk in SQL? Asterisk (*): In SQL, the columns for all the tables and views in the FROM clause will be displayed.

Define weak and strong entity sets?  Weak entity  set:  entity  set  that  do not  have  key  attribute  of  their  own are  known as weak entity sets.  Strong entity set

Find out the names of all employees who work for first Bank Corporation from database. SELECT EMPLOYEE_NAME FROM WORKS WHERE COMPANYNAME = ‘First Bank Corporation';

Nested Queries Let us see some more complex queries in this section. Sub-queries: Some of the basic concerns of sub-queries are: A sub-query is a SELECT statemen

Define various ways in which SELECT statement can be used for record selection Technology?  SELECT gives you control over a number of aspects for record retrieval: 1) Which