unitn-database-assignment

A crazy way to do my database assignment. With javascript, python and Java

What is the project

This project was an UNITN's Database course's assignment. The assignment consisted in executing some queries with python or Java to a PostgreSQL database. The eleven queries where very easy and the most difficult ones were the third and the fourth, in which one million random tuples were to be inserted. Whereas the right way of doing the assignment was creating a Java or python file that generated the queries and the random tuples sent with already made library functions, I chose to make an experiment.

The pdf assignment is this.

What did I do in the project

Using Node, I made a Javascript program that generated the queries. Than, it searched for all the .java and .py files in the src directory of my project and duplicated them in the dist directory, by replacing all the {{QUERY_N}} templates with the right query. The result was that the python or Java program in the dist folder, with all the queries already included as a literal string.

Why was that a bad idea

Of course this was only an experiment.

This was a bad idea because:

• The output file with all the queries (including the one with millions of inserts) weighted more than 200MB.
• Actually, the tuples were not random, because every execution of the program produced the same output.
• The Java compiler does not support huge literal strings. I had to gave up with it and it worked only with few inserts.
• The Python psycopg2 library does not support huge queries. It worked only when I splitted the one-million queries in twenty parts.
• It was extremly slow comparing with the build-in functions of Python and Java.

Why did I do it

I did it because:

• This was an opportunity to use an npm module made by my self. I used unitn-database-assignment to scan all the python and Java files in the src directory.
• Writing code to produce other code was funny.
• I used three quite languages in a project.
• I delivered my assignment late because my home network was quite slow in uploading the 215MB file.
• I used this project to try lots of testing frameworks, ci services and cover services.

Additional things I used

It is linted with eslint.

It is tested with:

• Mocha
• Jest
• Ava
• Tap
• Tape

I used nyc to generate the cover files.

I used as ci services:

• Travis.ci
• Circle.ci

I used as cover services:

• Coveralls
• Codecov

I used commitizen to commit responsively and unitn-database-assignment to generate the project tree.

How to run it

1. Install Node.js
2. Install python 3.7 and JDK
3. Add the psycopg2 python library with pip install psycopg2-binary
4. Execute npm i on the root folder of the project
5. Execute npm run transpile to generate the python and java files to the dist folder
6. Execute npm run serve:python to generate the dist files and also start the python program
7. Execute npm run serve:java to generate the dist files and also compile and run the java program. I will not work if you do not change the number of tuples in generator/config.js
8. Execute npm test (after having transpiled it) to execute all the tests with all the test frameworks. You can execute the tests with a specific test framework by running npm run test:test_framework.
9. Execute npm run directory-tree to generate the directory tree in the doc/tree folder.

How is structured the project

Made with dree.

unitn-database-assignment
 ├── LICENSE
 ├── README.md
 ├─> dist
 │   └── postgresql-42.2.8.jar
 ├─> doc
 │   ├─> assignment
 │   │   └── assignment.pdf
 │   └─> tree
 │       └── tree.txt
 ├── unitn-database-assignment.config.json
 ├─> generator
 │   ├── config.js
 │   ├── index.js
 │   └── queries.js
 ├── package-lock.json
 ├── package.json
 ├─> src
 │   ├── Database.java
 │   └── database.py
 └─> test
     ├─> ava
     │   ├── queries.test.js
     │   └── transpiling.test.js
     ├─> jest
     │   └── test.spec.js
     ├─> mocha
     │   └── test.js
     ├─> queries
     │   ├── eight.test.js
     │   ├── eleventh.test.js
     │   ├── fifth.test.js
     │   ├── first.test.js
     │   ├── ninth.test.js
     │   ├── second.test.js
     │   ├── seventh.test.js
     │   ├── sixth.test.js
     │   └── tenth.test.js
     ├─> tap
     │   ├── queries.test.js
     │   └── transpiling.test.js
     └─> tape
         ├── queries.test.js
         └── transpiling.test.js