Explain the rules for creating a labelled precedence graph, Database Management System

Assignment Help:

Explain the rules for creating a labelled precedence graph for testing view serializability.          

 Ans: A schedule S is view serializable if it is view equivalent to a serial schedule 

  • Each conflict serializable schedule is also view serializable
  • A schedule that is view serializable but not conflict serializable:

Testing for Serializability 

  • Refer some schedule of a set of transactions T1, T2... Tn
  • Precedence graph is a direct graph in which the vertices denote the transactions
  • We illustrate an arc from Ti to Tj if the two transaction conflict and Ti accessed the data item earlier on which the conflict arose
  • We may label the arc through the item on which the conflict arose. A schedule is conflict serializable if and only if its precedence graph is acyclic
  • If precedence graph is acyclic, the serializability order can be acquired by a topological sorting of the graph.
  • The trouble of checking if a schedule is view serializable falls in the class of NP-complete problems
  • Though practical algorithms that just check few sufficient conditions for view serializability can still be employed.

Related Discussions:- Explain the rules for creating a labelled precedence graph

Describe the ways for selecting data structure, Ways for Selecting Data Str...

Ways for Selecting Data Structure Algorithms operate on data structure. Therefore, selection of the best algorithm means selecting the best data structure from whole bunch. Th

What type of view of total database content, What type of view of total dat...

What type of view of total database content? Data base content Conceptual view of total database contain.

Need point of sale software for pizza restaurant, Project Description: N...

Project Description: Need Point of Sale software for pizza restaurant. Delivery and take out service, client's database, inventory control, order history, last order, order from

Entity relationship diagram, Ask questApollo Hospitals (AH) is a popular me...

Ask questApollo Hospitals (AH) is a popular medical service provider in Oman. AH wants to automate its business functions into an information system. The proposed information syst

Data analysis and design, give some example real-life situations where DBMS...

give some example real-life situations where DBMS are most suiitabe

Which data type can store unstructured data, Which data type can store unst...

Which data type can store unstructured data? Raw data type can store unstructured data.

What are the parts of sql language, What are the parts of SQL language? ...

What are the parts of SQL language? The SQL language has various parts: data - definitition language  Data manipulation language  View definition  Transaction contr

Timestamp type, Do NOT use the timestamp type.  Use separate date and time ...

Do NOT use the timestamp type.  Use separate date and time data types only.  Figure out how to define an SQL insert statement that uses built-in SQL (or MySQL) functions to define

To eliminate duplicate rows-data manipulation language, To eliminate duplic...

To eliminate duplicate rows (distinct operator)  Example: SELECT DISTINCT DEPTNO FROM EMP;

Payment processors, We have a buildup of payments that need to be processed...

We have a buildup of payments that need to be processed. You will need:- To prepare customer account on our site Process payment (you must have working Paypal account to d

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