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

Entity integrity constraint - relational constraints, It defines that no pr...

It defines that no primary key value can be null. This is as the primary key is used to recognize individual tuple in the relation. So we will not be able to recognize the records

Explain the dependency relationship of object oriented, Explain the depende...

Explain the dependency relationship of object oriented A dependency is a relationship which states that a change in specification of one thing can affect another thing, but n

When is a transaction rolled back, When is a transaction rolled back? A...

When is a transaction rolled back? Any changes that the aborted transaction made to the database must be uncompleted. While the changes caused by an aborted transaction have be

Define multivalued dependency and 4nf, Define multivalued dependency and 4N...

Define multivalued dependency and 4NF.  Ans:  Multivalued Dependency - Assume R be a relation schema and let α ⊆ R and β ⊆ R. The multivalued dependency  α →→β   holds o

Define- relational algebra, Define- relational algebra. The relational ...

Define- relational algebra. The relational algebra is a procedural query language. It having of a set of operations that take one or two relation as input and make a new relati

What is oracle process explain for processes of oracle, What is Oracle Proc...

What is Oracle Process? Explain any four processes started by Oracle. Oracle Process is as follows: SMON: The System Monitor carries out a crash recovery while a crashed in

E-R MODEL, WHAT IS MEANT BY E-R MODEL

WHAT IS MEANT BY E-R MODEL

Tuples-attributes , Consider a relation s over the attributes A and B wit...

Consider a relation s over the attributes A and B with the following characteristics: 5,000 tuples with 10 tuples per page A 2-level B+ tree index on attribute

Which is a legal expression in sql, Which is a legal expression in SQL? ...

Which is a legal expression in SQL? SELECT NAME FROM EMPLOYEE is a legal expression in SQL.

Normalization, Normalize the given relation to 3NF, justifying each step

Normalize the given relation to 3NF, justifying each step

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