nQuery

Generic SQL engine for Web and Big-data.

Install

NodeJS Version 0.8.0+

npm install node-query

Introduction

it could be used in some typical scenarios:

• As a SQL frontend, do syntax checking and formating.
• As a SQL engine for your KV databases like HBase or anything like that.
• Providing a SQL interface for your HTTP/WEB service.
• Do data merging and intergration among many different data sources like Oracle, MySQL, HBase etc.

Demo & Test

to run the demo, type the command:

node demo/demo.js

for the test , type the command:

make

read the demo carefully and then you could write own loader/adapter, there are also many test cases in test/unit, they would be great helpful to you.

Usage

please read the demo files demo/demo.js

for a KV storage engine ,what you need to do is providing the query interfaces like:

• singleQuery,
• rangeQuery,
• likeQuery

for a SQL storage engine, you should realize a function like :

function query(str, function(err, data) {
  ...  
})

then you could execute SQL like that : (code snippet from demo.js)

var sqls = [
  "SELECT * FROM kv.user WHERE id IN ('01', '03')",
  "SELECT * FROM kv.user WHERE id LIKE '1%'",
  "SELECT type, MAX(age), COUNT(id) FROM kv.user WHERE id BETWEEN '03' AND '10' GROUP BY type ORDER BY MAX(age) DESC",
  "SELECT * from mysql.shop where shop_id > 5"
]

var concurrentJoinSQL = [
  "$a := select * from kv.user where id BETWEEN '03' and '10'",
  "$b := select * from mysql.shop where shop_id > 5",
  "$c := select a.type , a.id ,b.name, b.title from $a INNER JOIN $b ON a.type = b.type WHERE a.id > '04'",
  "return $c"
]

var sequentialJoinSQL = [
  "$a := select * from kv.user where id BETWEEN '03' and '10'",
  //you could also use `unique` do filter firstly
  //"$type := UNIQUE($a.type)",
  //"$b := select * from mysql.shop where type = $type",
  "$b := select * from mysql.shop where type in $a.type",
  "$c := select a.type , a.id ,b.name, b.title from $a INNER JOIN $b ON a.type = b.type WHERE a.id > '04'",
  "return [$b, $c]"
]

As you see ,besides as a SQL computation level built on top of KV storage engine, it could do join operation among kv data source, sql sources, HTTP services now

nSQL Definition

The 'a little strange' sql as you see above, nSQL realize a subset of SQL92, and it also has some procedure features, it supports variables, it addes types of var / array / table, and also keyword return, for the details, please see the specification of peg/nquery.pgejs.

Task Scheduling

As you could see in concurrentJoinSQL ,we know that the tasks $a, $b have no relations, so nQuery would do them concurrently, but for the procedure of sequentialJoinSQL, $b is depending on $a,so task $b would be executed after the time $a completed

KeyWord return

In traditional SQL, the query result is a 2-D table , but In nSQL ,we add types of array / table,so now you could return complicated results like

return [$b, $c, 'hello', [1, 2]]

###Just Enjoy It!

Acknowledgements

• PegJS : http://pegjs.majda.cz/
• NodeJS : http://nodejs.org/
• BigQuery : https://developers.google.com/bigquery/docs/query-reference
• PL/SQL : http://docs.oracle.com/cd/B28359_01/appdev.111/b28370/fundamentals.htm#autoId0
• MySQL : http://dev.mysql.com/doc/refman/5.1/en/sql-syntax.html
• Impala : https://github.com/cloudera/impala/blob/master/fe/src/main/cup/sql-parser.y
• PgSQL : http://www.postgresql.org/docs/9.2/interactive/sql-syntax.html
• ql.io : http://ql.io