Define the wait for graph, Database Management System

Assignment Help:

Define the Wait for graph

Ans: The wait-for-graph is a directed graph and consist of nodes and directed arcs; the nodes of the graph are active transactions. An arc of the graph is inserted among two nodes if there is a data-item is needed by the node at the tail of the arc that is being held by the node at the head of the arc. If there is a transaction Ti, waiting for a data-item that is presently allocated and held by transaction Tj, after that there is a directed arc from the node for transaction Ti, to the node for transaction Tj. The wait-for-graph is employed for detection of deadlock in the system. If there is cycle exits in the graph, all the transaction (denoted as nodes) are in deadlock, which are in the cycle.


Related Discussions:- Define the wait for graph

Keys - relational database integrity, Candidate Key:  In a relation R, a ca...

Candidate Key:  In a relation R, a candidate key for R is a subset of the set of attributes of R, which have the differnt two properties: (1)        Uniqueness:                N

What count function return in sql, What Count function return in SQL? C...

What Count function return in SQL? Count function within SQL returns the number of values. (Count function counts all the not null values in the exact column. If we need to cou

List the data structures implemented by the storage manager, List the data ...

List the data structures implemented by the storage manager. The storage manager executes the following data structure a) Data files b) Data dictionary c) indices

What is the meaning of redundant associations, Adding Redundant Association...

Adding Redundant Associations for Efficient Access The expression redundant association means using "duplicate association for proficient access". While analysis, it is not a

Determine the minimal set of functional dependencies, Determine the minimal...

Determine the minimal set of functional dependencies for the following data. This table is part of the OHSU database of extracurricular activities and tracks the DMICE band's co

The maximum no of key fields that can be used in a header, The Maximum no o...

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

What is property - properties of a database, What is property - properties ...

What is property - properties of a database ? It is an integrated collection of logically related records. It consolidates separate files into a common pool of data records and

Multi-list file organisation, Multi-list file Organisation Multi-list f...

Multi-list file Organisation Multi-list file organisation is a multi-index linked file organisation. A linked file organisation is a logical organisation where physical orderin

What is the use of rename operation, What is the use of rename operation? ...

What is the use of rename operation? Rename operation is used to rename both relations and an attributes. It uses the as clause, taking the form: Old-name as new-name.

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

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!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd