Query-Engine

A node.js query engine for university courses and rooms, supporting RESTful Web service

Project configuration

Before running the project app, execute the following commands to prepare the project's tooling and dependencies.

OS X / Linux:

1. yarn run clean

2. yarn install

3. yarn run build

Windows:

1. yarn run cleanwin

2. yarn install

3. yarn run build

Overview of project files and API

Source code for populating data and handling query is in the file InsightFacade.ts

Source code for RESTful web services is in the file Server.ts

All test files are in the folder /test

The major APIs are the following:

• addDataset(id: string, content: string): adds a dataset to the internal model, providing the id of the dataset, and the string of the content of the dataset.

• removeDataset(id: string): removes a dataset from the internal model, given the id.

• performQuery(query: any): performs a query on the dataset. It first should parse and validate the input query, then perform semantic checks on the query, and finally evaluate the query if it is valid.

Query Syntax

QUERY ::='{'BODY ', ' OPTIONS  (', ' TRANSFORMATIONS)? '}'

BODY ::= 'WHERE: {' (FILTER)? '}'
OPTIONS ::= 'OPTIONS: {' COLUMNS (', ' SORT)? '}'
TRANSFORMATIONS ::= 'TRANSFORMATIONS: {' GROUP ', ' APPLY '}'

FILTER ::= (LOGICCOMPARISON | MCOMPARISON | SCOMPARISON | NEGATION)

LOGICCOMPARISON ::= LOGIC ': [{' FILTER ('}, {' FILTER )* '}]'  
MCOMPARISON ::= MCOMPARATOR ': {' m_key ':' number '}'  
SCOMPARISON ::= 'IS: {' s_key ': ' [*]? inputstring [*]? '}'  
NEGATION ::= 'NOT: {' FILTER '}'

LOGIC ::= 'AND' | 'OR' 
MCOMPARATOR ::= 'LT' | 'GT' | 'EQ' 

COLUMNS ::= 'COLUMNS:[' (string ',')* string ']'
SORT ::= 'ORDER: ' ('{ dir:' DIRECTION ', keys: [ ' string (',' string)* ']}' | string) 
DIRECTION ::= 'UP' | 'DOWN'  

GROUP ::= 'GROUP: [' (key ',')* key ']'                                                          
APPLY ::= 'APPLY: [' (APPLYKEY (', ' APPLYKEY )* )? ']'  
APPLYKEY ::= '{' string ': {' APPLYTOKEN ':' key '}}'
APPLYTOKEN ::= 'MAX' | 'MIN' | 'AVG' | 'COUNT' | 'SUM'

key             ::= (s_key | m_key)
                    //semantics for each key detailed below

s_key           ::= ('courses_'('dept' | 'id' | 'instructor' |
                                'title' | 'uuid')) | 
                    ('rooms_'('fullname' | 'shortname' | 'number' | 
                              'name' | 'address' | 'type' | 
                              'furniture' | 'href'))           
m_key           ::= ('courses_'('avg' | 'pass' | 'fail' | 'audit' | 'year')) |
                    ('rooms_'('lat' | 'lon' | 'seats))      

inputstring     ::= [^*]+ //one or more of any character except asterisk.

Query Examples

Query A:

Description: Find all rooms with more than 300 seats, and has "Tables" in the furniture description. Then, group all the rooms by the building they are in (rooms_shortname). For each of these groups, show the number of seats in the room with the most seats from that group. Show the groups' shortnames and the largest number of seats in the group, sorted by the largest number of seats in the group, largest to smallest.

{
    "WHERE": {
        "AND": [{
            "IS": {
                "rooms_furniture": "*Tables*"
            }
        }, {
            "GT": {
                "rooms_seats": 300
            }
        }]
    },
    "OPTIONS": {
        "COLUMNS": [
            "rooms_shortname",
            "maxSeats"
        ],
        "ORDER": {
            "dir": "DOWN",
            "keys": ["maxSeats"]
        }
    },
    "TRANSFORMATIONS": {
        "GROUP": ["rooms_shortname"],
        "APPLY": [{
            "maxSeats": {
                "MAX": "rooms_seats"
            }
        }]
    }
}

Response A:

{
    "result": [{
        "rooms_shortname": "OSBO",
        "maxSeats": 442
    }, {
        "rooms_shortname": "HEBB",
        "maxSeats": 375
    }, {
        "rooms_shortname": "LSC",
        "maxSeats": 350
    }]
}

Query B:

Description: Find all courses with average of 97 or above

{
  "WHERE":{
     "GT":{
        "courses_avg":97
     }
  },
  "OPTIONS":{
     "COLUMNS":[
        "courses_dept",
        "courses_avg"
     ],
     "ORDER":"courses_avg"
  }
}

Response B:

{ 
 result:
  [ { courses_dept: 'epse', courses_avg: 97.09 },
    { courses_dept: 'math', courses_avg: 97.09 },
    { courses_dept: 'math', courses_avg: 97.09 },
    { courses_dept: 'epse', courses_avg: 97.09 },
    { courses_dept: 'math', courses_avg: 97.25 },
    { courses_dept: 'math', courses_avg: 97.25 },
    { courses_dept: 'epse', courses_avg: 97.29 },
    { courses_dept: 'epse', courses_avg: 97.29 },
    { courses_dept: 'nurs', courses_avg: 97.33 },
    { courses_dept: 'nurs', courses_avg: 97.33 },
    { courses_dept: 'epse', courses_avg: 97.41 },
    { courses_dept: 'epse', courses_avg: 97.41 },
    { courses_dept: 'cnps', courses_avg: 97.47 },
    { courses_dept: 'cnps', courses_avg: 97.47 },
    { courses_dept: 'math', courses_avg: 97.48 },
    { courses_dept: 'math', courses_avg: 97.48 },
    { courses_dept: 'educ', courses_avg: 97.5 },
    { courses_dept: 'nurs', courses_avg: 97.53 },
    { courses_dept: 'nurs', courses_avg: 97.53 },
    { courses_dept: 'epse', courses_avg: 97.67 },
    { courses_dept: 'epse', courses_avg: 97.69 },
    { courses_dept: 'epse', courses_avg: 97.78 },
    { courses_dept: 'crwr', courses_avg: 98 },
    { courses_dept: 'crwr', courses_avg: 98 },
    { courses_dept: 'epse', courses_avg: 98.08 },
    { courses_dept: 'nurs', courses_avg: 98.21 },
    { courses_dept: 'nurs', courses_avg: 98.21 },
    { courses_dept: 'epse', courses_avg: 98.36 },
    { courses_dept: 'epse', courses_avg: 98.45 },
    { courses_dept: 'epse', courses_avg: 98.45 },
    { courses_dept: 'nurs', courses_avg: 98.5 },
    { courses_dept: 'nurs', courses_avg: 98.5 },
    { courses_dept: 'epse', courses_avg: 98.58 },
    { courses_dept: 'nurs', courses_avg: 98.58 },
    { courses_dept: 'nurs', courses_avg: 98.58 },
    { courses_dept: 'epse', courses_avg: 98.58 },
    { courses_dept: 'epse', courses_avg: 98.7 },
    { courses_dept: 'nurs', courses_avg: 98.71 },
    { courses_dept: 'nurs', courses_avg: 98.71 },
    { courses_dept: 'eece', courses_avg: 98.75 },
    { courses_dept: 'eece', courses_avg: 98.75 },
    { courses_dept: 'epse', courses_avg: 98.76 },
    { courses_dept: 'epse', courses_avg: 98.76 },
    { courses_dept: 'epse', courses_avg: 98.8 },
    { courses_dept: 'spph', courses_avg: 98.98 },
    { courses_dept: 'spph', courses_avg: 98.98 },
    { courses_dept: 'cnps', courses_avg: 99.19 },
    { courses_dept: 'math', courses_avg: 99.78 },
    { courses_dept: 'math', courses_avg: 99.78 } ] }

Sidenotes

All zip files are used for testing purposes.