Seed code - Boilerplate for step 1 - Database Engine Assignment

Problem Statement

As an initial step of building a Utility to get meaningful information out of our Raw data - **as a first step you should be able to parse (decipher) our question. In our computing terms, we call this a query.**Our system should be able to interpret this and break it into several parts - so that necessary actions can be triggered to fetch the required information in the proper format.

STEP 1 - Deciphering the parts of the String (Query)

Please note that the End User interacting with this utility will give out SQL like instructions and would expect the system to respond with necessary information. The system perceives this as a String of characters and we should manipulate and break this string into appropriate Data Structures. For Instance,

Query: SELECT winner, Count( winner ) FROM ipl.csv WHERE win_by_runs > 100 GROUP BY winner ORDER BY winner;

Sample Data:

winner	count (winner)
Kings XI Punjab	1
Kolkata Knight Riders	1
Rajasthan Royals	1
Royal Challengers Bangalore	3

Query: SELECT city, winner FROM ipl.csv WHERE winner='Chennai Super Kings' AND city ='Abu Dhabi' AND season=2014;

Sample Data:

city	winner
Abu Dhabi	Chennai Super Kings

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Few terms need to understand before starting the project.

1. select ->  get the required information

2. '*' ->  select all the fields 

3. where ->  filter result

4. order by ->  sort the result based on particular field

5. group by ->  get the records together based  on particular field.

6. aggregate ->  There are 5 aggregates,they are "sum,count,min,max,avg".  

7. Example query string :  select season,winner,player_match from ipl.csv where season > 2014 and city = 'Bangalore';

    a. fetching season, winner, player_match 

    b. from the file ipl.csv  (csv -> Comma Separated Value)

    c. where - filter the results. Get the details of the matches played in Bangalore after season 2014
    
    d. ipl.csv - name of the file from which we need to fetch the information/records

---

Our STEP 1 involves two tasks, given below:

a. Write a program to read the query string as input and split them into words. Print the output on console as given below:

Input String : 	select * from ipl.csv where season > 2014 and city = 'Bangalore'

Output String: 	select
			    * 
			    from 
			    ipl.csv  
			    where  
			    season
			    > 
			    2014
			    and 
			    city
			    =
			    'bangalore'

b. Further enhance your program to now extract certain parts of the same query:

i. Get only file name from the query string.

	Input String : select * from ipl.csv where season > 2014 and city = 'Bangalore'
	Output String : ipl.csv


ii. Get only base part(before `where` word) of the query from the given query string. 

	Input String : select * from ipl.csv where season > 2014 and city = 'Bangalore'
	Output String : select * from ipl.csv 

iii. Get only filter part(after `where` word) of the query from the given query string. 

	Input String : select * from ipl.csv where season > 2014 and city = 'Bangalore'
	Output String : season > 2014 and city ='bangalore'

iv. As there will be multiple conditions, seperate each condition and display in different line.
    
    Input String : select * from ipl.csv where season > 2014 and city = 'Bangalore'
	Output String : 
                	          season > 2014 
                              city ='bangalore'
	                
v.  Extract the logical operators in sequence from the given query string. 
    Note: Logical operators are "and, or, not"
    
    Input String : select season,winner,player_match from ipl.csv where season > 2014 and city ='Bangalore' or date > '31-12-2014'
    Output String : 
	        and
	        or
	        
vi. Extract the selected fields/information from the given query.

    Input String : select city,winner,player_match from ipl.csv where season > 2014 and city = 'Bangalore'
	Output String :
        	city
        	winner
        	player_match

vii. Extract the order by field from the given string.
    Note : user may need the information in sorted order of a particular field.
    
    Input String : select * from ipl.csv where season > 2016 and city= 'Bangalore' order by win_by_runs
	Output String : win_by_runs

viii. Extract the group by field from the given string.
    Note : user may need the related information grouped together.
    For Example they may require to see the information department wise.
    
    Input String : select team1, sum(win_by_runs) from ipl.csv where season > 2016 and city= 'Bangalore' group by team1
	Output String : team1

ix. User may required the information like who is getting maximum salary or minimum age etc.. these are called aggregate functions (minimum, maximum, count, average, sum)

    Input String : select avg(win_by_wickets),min(win_by_runs) from ipl.csv 
	Output String : 
	             avg(win_by_wickets)
                 min(win_by_runs)
            
   	Note:  Other parts like where clause, order by, group by may be present in the query.

Expected solution

Displaying various components/parts of the query like selected fields, conditional parts, aggregate fields, groupBy field, OrderBy field

Project structure

The folders and files you see in this repositories, is how it is expected to be in projects, which are submitted for automated evaluation by Hobbes

Project
|
├── data 			        // If project needs any data file, it can be found here/placed here, if data is huge they can be mounted, no need put it in your repository
|
├── com.stackroute.datamunger	    // all your java file will be stored in this package
|	└── DataMunger.java	            // This is the main file, all your logic is written in this file only
├── com.stackroute.datamunger.test // all your test cases will be stored in this package
|	└── DataMungerTest.java	        // all your test cases are written using JUnit, these test cases can be run by selecting Run As -> JUnit Test 
|
├── .classpath			        // This file is generated automatically while creating the project in eclipse
|
├── .hobbes   			        // Hobbes specific config options, such as type of evaluation schema, type of tech stack etc., Have saved a default values for convenience
|
├── .project			            // This is automatically generated by eclipse, if this file is removed your eclipse will not recognize this as your eclipse project. 
|
├── pom.xml 			            // This is a default file generated by maven, if this file is removed your project will not get recognised in hobbes.
|
└── PROBLEM.md  		            // This files describes the problem of the assignment/project, you can provide as much as information and clarification you want about the project in this file

PS: All lint rule files are by default copied during the evaluation process, however if need to be customizing, you should copy from this repo and modify in your project repo

To use this as a boilerplate for your new project, you can follow these steps

1. Clone the base boilerplate in the folder assignment-solution-step1 of your local machine

   git clone https://gitlab-wd.stackroute.in/stack_java_datamunging/step1-boilerplate.git assignment-solution-step1

2. Navigate to assignment-solution-step1 folder

   cd assignment-solution-step1

3. Remove its remote or original reference

   git remote rm origin

4. Create a new repo in gitlab named assignment-solution-step1 as private repo

5. Add your new repository reference as remote

   git remote add origin https://gitlab.training.com/{{yourusername}}/assignment-solution-step1.git

   Note: {{yourusername}} should be replaced by your username from gitlab

6. Check the status of your repo

   git status

7. Use the following command to update the index using the current content found in the working tree, to prepare the content staged for the next commit.

   git add .

8. Commit and Push the project to git

   git commit -a -m "Initial commit | or place your comments according to your need"

   git push -u origin master

9. Check on the git repo online, if the files have been pushed

Important instructions for Participants

• We expect you to write the assignment on your own by following through the guidelines, learning plan, and the practice exercises
• The code must not be plagirized, the mentors will randomly pick the submissions and may ask you to explain the solution
• The code must be properly indented, code structure maintained as per the boilerplate and properly commented
• Follow through the problem statement shared with you

Further Instructions on Release

*** Release 0.1.0 ***

• Right click on the Assignment select Run As -> Java Application to run your Assignment.
• Right click on the Assignment select Run As -> JUnit Test to run your Assignment.