rusco / challenge

Backend Challenge App

Backend Challenge

Loader and Webserver for the Backend challenge according the specification in the docs folder.

This package contains 2 deliveries, one each in the folder "loader" and "server". Please refer to the README.md files in these folders.

Roadmap

For the next version 1.1 significant performance enhancements regarding the sql statements "top-zones" and "zone-trips" are planned.

The version 1.1 database schema will include integrate pu_zone and do_zone in a new "alltrips" table.

Version 1.1 Database Changes:

-- migration scripts from current schema to new schema: 
 CREATE TABLE IF NOT EXISTS alltrips (
    pu_datetime     TEXT,
    do_datetime     TEXT,
    pu_locationid   INTEGER,
    do_locationid   INTEGER,
    color           TEXT,
    pu_locationzone TEXT,
    do_locationzone TEXT
);

CREATE INDEX pu_location_idx ON alltrips (
    pu_locationid
);
CREATE INDEX do_location_idx ON alltrips (
    do_locationid
);

INSERT INTO alltrips 
    SELECT t.pu_datetime,
        t.do_datetime,
        t.pu_locationid,
        t.do_locationid,
        t.color,
        z.zone pu_locationzone,
        z2.zone do_locationzone
    FROM trips t
        LEFT JOIN
        zones z ON z.locationid = t.pu_locationid
        LEFT JOIN
        zones z2 ON z2.locationid = t.do_locationid;

--afterwards: 
DROP TABLE trips; 
DROP TABLE zones; 




--new top-zones sqlt statement v1.1 : 
 WITH pucount AS (
    SELECT pu_locationzone,
           pu_locationid,
           count(pu_locationid) pu_total
      FROM alltrips t
     GROUP BY pu_locationid
     ORDER BY count(pu_locationid) DESC
),
docount AS (
    SELECT do_locationzone,
           do_locationid,
           count(do_locationid) do_total
      FROM alltrips t
     GROUP BY do_locationid
     ORDER BY count(do_locationid) DESC
)
SELECT *
  FROM pucount
       LEFT JOIN
       docount ON pucount.pu_locationid = docount.do_locationid 
 --ORDER BY pu_total DESC
 ORDER BY do_total DESC
  
 LIMIT 5;
 
 --new zone-trips sql statement v1.1:
  SELECT z.pu_locationzone,
       count(CASE WHEN a.pu_locationid = 36 AND date(a.pu_datetime) = date('2018-01-12') THEN 1 END) pu_count,
       count(CASE WHEN a.do_locationid = 36 AND date(a.do_datetime) = date('2018-01-12') THEN 1 END) do_count
  FROM alltrips a, (SELECT pu_locationzone FROM alltrips WHERE pu_locationid = 36 LIMIT 1) z;
	   
	   
 --list-yellow statement v1.1:
 SELECT pu_datetime,
       do_datetime,
       pu_locationid,
       do_locationid
  FROM alltrips t
 WHERE COLOR = 'yellow'
 --- ...

Have Fun !