数据库代写 | Distributed Databases and Data Mining Assignment 2

本次澳洲代写是分布式数据库和数据挖掘的一个assignment

Introduction

Assignment 2 has four questions. Both UG and PG students need to finish all four questions. The first two
questions are the same for UG and PG students, while the last two questions have different requirements for UG
and PG students.

Please answer the questions in the format of descriptions, equations, query graphs and the operator trees in
question 1-4. Only the query graph and the operator tree can be handwritten; others such as descriptions and
equations must be in electronic version. For the handwritten parts, you could save them as jpg. or png., and
insert them into office word. Please submit the electronic version and do not submit the handwritten version of
descriptions and equations. Handwritten descriptions and equations will not be marked.

You are expected to provide your answers for the all four questions in one pdf and submit the pdf in MyUni,
Assignment 2.

If you have any questions about assignment 2, please feel free to post the questions on the discussion board or
contact Congbo Ma (congbo.ma@adelaide.edu.au).

Questions

Question 1 (4 marks):

Given three relations STUDENT, COURSE and MARK, a user query is: “Find the student name and Course name of
students whose scores are more than 85 points.”

(1) Please give the claculus query (SQL) (1 mark);
(2) Please give the corresponging query graph (2 mark);
(3) Please map the SQL query into an original operator tree (Not optimized) (1 mark).

Question 2 (4 marks):

For the following query:

SELECT SNAME, CNAME
FROM STUDENT, COURSE, MARK
WHERE (SAGE < 16
OR MARK.CID <”C2″)
AND (CCONTEXT = “Science”
OR SCORE > 85)
AND STUDENT.SID = MARK.SID
AND (CCONTEXT = “Science”
OR SCORE ≤ 85)
AND COURSE.CID = MARK.CID

(1) Please simplify the query (2 mark);

(2) Please transform the SQL expression into an optimized operator tree using the restructuring algorithm where
select and project operations are applied as soon as possible to reduce the size of intermediate relations (2 mark).


程序代写代做C/C++/JAVA/安卓/PYTHON/留学生/PHP/APP开发/MATLAB


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