本次Java代写是创建Derby和mongodb数据库并实现一个heap file
COSC2406/2407 – Database Systems
Assignment #1
Task 1: Derby
You are required to load the data into Derby. In your report:
• explain how have you chosen to structure the Derby relational database and give reasons.
• provide details of the time to load the data into Derby. You need to analyse the data and
consider appropriate ways to structure the data and then using any scripting, programming
or other tools to format the data accordingly.
• Postgraduate students only: What alternative way or ways could you have organised
the data when storing in Derby, and what advantages or disadvantages would these alternative designs have?
Task 2: MongoDB
You are required to load the data into MongoDB. In your report:
• explain how have you chosen to structure the data inserted in MongoDB
• provide details of the time taken to load the data (The mongoimport is one utility will
provide such information). Please note that a naive import into a flat structure in Mongodb
will not accrue you a great mark. You need to analyse the data and consider appropriate
ways to structure the data and then using any scripting, programming or other tools to
format the data accordingly.
• Postgraduate students only: What alternative way or ways could you have organised
the data when storing in MongoDB, and what advantages or disadvantages would these
alternative designs have?
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Task 3: Implement Heap File in Java
Set up a git repository for your code, and complete the following programming tasks using Java
on the AWS linux instance assigned to you.
A program to load a database relation writing a heap file
The source records are variable-length. Your heap file may hold fixed-length records (you will
need to choose appropriate maximum lengths for each field). However, you may choose to
implement variable lengths for some fields, especially if you run out of disc space or secondary
memory!
All attributes with Int type must be stored in 4 bytes of binary, e.g. if the value of ID is equal
to 70, it must be stored as 70 (in decimal) or 46 (in hexadecimal; in Java: 0x46). It must not be
stored as the string “70”, occupying two bytes. Your heap file is therefore a binary file.
For simplicity, the heap file does not need a header (containing things like the number of
records in the file or a free space list), though you might need to keep a count of records in each
page. The file should be packed, i.e. there is no gap between records, but there will need to be
gaps at the end of each page.
The executable name of your program to build a heap file must be dbload and should be
executed using the command:
java dbload -p pagesize datafile
The output file will be heap.pagesize where your converted binary data is written as a heap.
Your program should write out one “page” of the file at a time. For example, with a
pagesize of 4096, you would write out a page of 4096 bytes possibly containing multiple
records of data to disk at a time. You are not required to implement spanning of records across
multiple pages.
Your dbload program must also output the following to stdout, the number of records
loaded, number of pages used and the number of milliseconds to create the heap file.
A program that performs a text search using your heap file
Write a program to perform text query search operations on the field “BLD NAME” heap file
(without an index) produced by your dbload program in Section 4.
The executable name of your program to build a heap file must be dbquery and should be
executed using the command:
java dbquery text pagesize
Your program should read in the file, one “page” at a time. For example, if the pagesize
parameter is 4096, your program should read in the records in the first page in heap.4096
from disk. These can then be scanned, in-memory, for a match (the string in text parameter is
contained in the field “BLD NAME”). If a match is found, print the matching record to stdout,
there may be multiple answers. Then read in the next page of records from the file. The process
should continue until there are no more records in the file to process.
In addition, the program must always output the total time taken to do all the search operations in milliseconds to stdout.
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5 General Requirements and Getting Help
This section contains information about the general requirements that your assignment must
meet and how to get help.
1. Your database and Java programs must be set up and run on the AWS linux machine
assigned to you for this course.
2. Your database must be set up on your AWS linux instance (as set up following the instructions in the initial practical classes in the laboratories).
3. You must implement your program in Java. Your program must be well written, using
good coding style and including appropriate use of comments (that clearly identify the
changes you are making to the code). Your markers will look at your source code. Coding
style will form part of the assessment of this assignment.
4. If your marker cannot compile your programs, you risk yielding zero marks for the coding
component of your assignment.
5. Your Java program may be developed on any machine, but must compile and run your
AWS linux instance.
6. You must use git as you develop your code (wherever you do the development). As you
work on the assignment you should commit your changes to git regularly (for example,
hourly or each time you rebuild) as the log may be used as evidence of your progress.
7. Paths must not be hard-coded.
8. Diagnostic messages must be output to stderr.
9. Parts of this assignment will ask you to analyse your results, and to write your conclusions in a report. The report MUST be a PDF file. Submissions that do not meet this
requirement will NOT be marked.
10. Your report must be well-written. Poorly written or hard to read reports will receive
substantially lower marks. Your report should be appropriate to submit in a professional
environment (such as including in a portfolio of your work for a prospective employer).
The RMIT Study & Learning Centre employs advisors to help you improve your writing.
For details, see http://www.rmit.edu.au/studyandlearningcentre.
11. All sections of this assignment are expected to show that you have thought about the
problem. The most basic structuring of data and analysis will get the most basic mark.
12. Canvas for COSC2406/COSC2407 Database Systems contains a discussion board for this
assignment allowing a forum for students to ask questions (see below) and contribute
to discussion about aspects of the assignment. If there are announcements about the
assignment (including if there are any revisions to the assignment specification) these
will also be made via announcements on Canvas. You are expected to check these on a
daily basis. Login through https://my.rmit.edu.au.
13. If you have any questions about the assignment (for example to clarify requirements):
(a) Please first check this assignment specification, as well the announcements and the
discussion board on canvas to see if it has already been answered.
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(b) If it has NOT already been answered and does NOT include your own code (including database queries), please post your question on the discussion board.
(c) Otherwise, if your question involves your own code (or is about your personal situation) then discuss it in your practical class with the lab instructor or contact the
lecturer (or your tutor) via email.
6 Submission
Before you submit anything, read through the assignment specifications again carefully, especially Section 5. Check that you have followed ALL instructions. Also check that you have
attempted all parts of all tasks in Section 4.
When
The assignment is due at 11.59pm on Tuesday 31 March 2020.
What
You MUST submit:
1. your report (a single PDF file) that explains your approach and answers for each task (1,
2 and 3) and includes any scripts, queries you used, and output; and
2. a zip file of your code for task 3(all Java sources files including your git log)
How
You need to submit your report in one PDF file using the link under “Assesments” on the course
blackboard through myRMIT by 11.59pm on Tuesday 31 March 2020.
Late submissions should be submitted using the same Blackboard procedure, but will be
penalised by 10% of total possible marks per day for assignments that are late 1 to 5 days late.
For assignments that are more than 5 days late, a penalty of 100% will apply.
You should ensure that your score from the turnitin similarity checker is in the green range.
Any greater similarity ( yellow , orange or red ) will be flagged for closer inspection.
7 Marking Criteria and Weighting
Marking criteria will include: (i) appropriate design of databases, (ii) correctness of scripts,
queries, and explanations (iii) completeness of results, (iv) clarity and quality of justifications
and explanations (v) depth of critical analysis.
Task 1: Derby 25 points
• scripts for shaping data
• justification for scripts and explanation of chosen design
• explanation and analysis of alternative designs
• queries for Derby
Task 2: MongoDB 25 points
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• scripts for shaping data
• justification for scripts and explanation of chosen design
• explanation and analysis of alternative designs
Task 3: Heap file in Java 50 points
• implementation of heap file and text search
• queries for Java
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