Design a query plan for distributed query, Database Management System

Assignment Help:

(a) Design a query plan for the following distributed query: An application at site B wants to compute a join of STUDENT ?Id=StudId TRANSCRIPT where STUDENT (Id,Major) is at site B and TRANSCRIPT (StudId, CrsCode) is at site C. The result should be returned to B. Assume that semijoin is not used. Also assume that

  • Value lengths are:
  1. Id and StudId are 8 bytes long;
  2. Major is 3 bytes long;
  3. CrsCode is 6 bytes long.
  • STUDENT has 15,000 tuples.
  • 6,000 students are registered for at least one course. On the average, each student is registered for 5 courses.

(b)   Estimate the cost of computing σMajor='CS' (STUDENT) ?Id = StudId TRANSCRIPT using the semijoin strategy. Use the sizes of the STUDENT and TRANSCRIPT relations and of their attributes from the part (a) above. In addition, assume that 10% of the students major in CS. Compare this with the solutions in part (a) above that do not use the semijoin.

 


Related Discussions:- Design a query plan for distributed query

Which method of access uses key transformation, Which method of access uses...

Which method of access uses key transformation? A Hash method of access uses key transformation.

ER diegrams, How to draw an ER diagram to a finance companz

How to draw an ER diagram to a finance companz

Describes the several relationship constraints, Describes the several relat...

Describes the several relationship constraints through giving suitable example? Constraints on relationships: There are two kinds of constraints on relationships. 1) Mapping

Explain two phase locking protocol, Explain Two phase locking protocol ...

Explain Two phase locking protocol A transaction is consider as to follow the two-phase locking protocol if all locking operations precede the first unlock operation in the tra

Define variable-length records arise in database, What are the ways in whic...

What are the ways in which the variable-length records arise in database systems? Storage of many record types in a file. Record types that permit variable lengths for one o

What are the ways in which signal can be generated, What are the ways in wh...

What are the ways in which signal can be generated A signal might be generated in many ways such as a Signal is result of particular physical condition. Whenever a process writ

What is a database, What is a database? Database - Basically in simpl...

What is a database? Database - Basically in simple terms A database is a collection of inter related data and/or information stored so which it is available to several users

Describe relational model, Describe relational model? Structure of rela...

Describe relational model? Structure of relational data base Basic structure Database schema Keys Schema diagram Query languages

Aims of the design project, The aims of the project are: 1. To enable th...

The aims of the project are: 1. To enable the students to undertake the detailed design of a specific plant or process 2. The design projects includes: process selection; und

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