Describe the algorithm to draw the dependency graph, Database Management System

Assignment Help:

Describe the algorithm to draw the dependency graph?  

Ans: Algorithm to draw Precedence Graph is like this:

a.  For every transaction Ti participating in schedule S, make a node labeled Ti in the precedence graph.

b.  For every case in S where Tj executes a read_item(X) after Ti executes a write_item(X), create an edge (Ti→Tj) in the precedence graph.

c.  For every case in S where Tj executes a write_item(X) after Ti executes a read_item(X), create an edge (Ti→Tj) in the precedence graph.

d.  For every case in S where Tj executes a write_item(X) after Ti executes a write_item(X), create an edge (Ti→Tj) in the precedence graph.

e.  The schedule S is serializable if and only if the precedence graph has no cycles.


Related Discussions:- Describe the algorithm to draw the dependency graph

Why were functional methods fashionable in early days, Why were functional ...

Why were functional methods fashionable in early days? These are inspired directly by computer architecture and thus popular among computer scientist in early days. The divisio

Calculate the joint probability, Consider the following frequency counts o...

Consider the following frequency counts of some itemsets in a transaction database r : freq({A}, r) = 0.405 freq({B}, r) = 0.510 freq({C}, r) = 0.303 freq({A

Can a filed occur in several field groups, Can a filed occur in several fie...

Can a filed occur in several field groups. Yes.  But it leads to redundant data redundancy.

What is data integrity, What is data integrity? Ans: It is the data con...

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

Advantages to copying records from one table to another, What kind of advan...

What kind of advantages to copying records from one table to another? -) When an algorithm that modifies a table is used after that it's safer to work with the copy -) When

Create a table for database transformation , Step 1 . Using Oracle, create ...

Step 1 . Using Oracle, create the tables identified in the preferred solution for Assignment 2. Technicians (ZipCode, TechnicianID, FirstName, LastName, Street, City, State, Home

What is database trigger, What is database Trigger? A database trigger ...

What is database Trigger? A database trigger is a PL/SQL block that can explained to automatically execute for insert, update, and delete statements against a table. The trigge

What is a cascading update, What is a cascading update? Referential int...

What is a cascading update? Referential integrity constraints needs that foreign key values in one table correspond to primary key values in another. If the value of the primar

What is a query tree, What is a query tree?     Ans:  A query tree, as ...

What is a query tree?     Ans:  A query tree, as well known as operator graph, is a tree data structure that corresponds to a relational algebra expression. It denotes the inpu

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