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

Create a database, Project: Microsoft Access You have been asked by the ...

Project: Microsoft Access You have been asked by the ABC Tanning Salon to create a database that can be used to track the salon's customers.  You are to create a table in Access

What is aggregate function, What is aggregate function? Briefly describe it...

What is aggregate function? Briefly describe it? Aggregate functions are functions that take a collection of values as input and return a one value. SQL offers 5 built-in aggre

Abap/4 statements to access internal tables without header, What should be ...

What should be declared explicitly in the corresponding ABAP/4 Statements to access internal tables without header lines & why? Work Area. This is needed as the Work Area is

List the reg-no of vehicles owned in relational algebra, Given the followin...

Given the following relations Vehicle (Reg_no, make, colour) Person(eno, name, address) Owner(eno, reg_no) Write expressions in the relational algebra to answer the following

What is bcnf boyce-codd normal form, BCNF Boyce-Codd Normal Form A rel...

BCNF Boyce-Codd Normal Form A relation schema R is in BCNF if it is in 3NF and accepts an additional constraint that for every FD X A, X has to be a candidate key. If a relati

Aggregation, Design a database for an airline.The database must keep track ...

Design a database for an airline.The database must keep track of customers and their reservations,flights and their status, seat assignment on individual flights and, the schedule

Data base model, why are older data base model are being replaced by new da...

why are older data base model are being replaced by new data model

Example of equijoin, Example: Consider the following relations: ...

Example: Consider the following relations: ROLLNO NAME ADDRESS COURSE_ID 100 Ka

How many types of users works on database, How many types of users works on...

How many types of users works on database? Users are differentiated through the way they expect to interact along with the system (i) Application programmers-interact with

Explain the process-oriented decomposition, Breaking into Subsystems D...

Breaking into Subsystems Decomposition is a significant technique for coping with complexity based on idea of divide and conquers. In dividing a problem into sub problems, the

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