level-sql

MOTIVATION

So you are happy with your very small, very fast key value store. But now for some reason you think you need SQL. Ok, fine. Here is a module.

USAGE

Given the following key/values

key1  { a: 0, b: 1 }
key2  { a: 2, b: 3 } 

And some boilerplate

var level = require('level');
var sql = require('level-sql');

var db = level('./db', { valueEncoding: 'json' });
sql(db);

Select Any

Given a table T, the query SELECT * FROM T will result in all the elements of all the rows of the table being shown.

var stream1 = db.query('SELECT * from table1');

{ "key": "key1", "value": { "a": 0, "b": 1 } }
{ "key": "key2", "value": { "a": 2, "b": 3 } }

Select Specific

With the same table, the query SELECT K FROM T will result in the elements from the key K of all the rows of the table being shown.

var stream1 = db.query('SELECT a from table1');

{ "key": "key1", "value": { "a": 0 } }
{ "key": "key2", "value": { "a": 2 } }

Where Clauses

With the same table, the query SELECT * FROM T WHERE K1 = 2 will result in all the elements of all the rows where the value of column K1 is 2 being shown — in Relational algebra terms, a selection will be performed, because of the WHERE clause. This is also known as a Horizontal Partition, restricting rows output by a query according to specified conditions. There can be as many conditions as you want separated by and or or.

var stream1 = db.query('SELECT a from table1 WHERE a = 2 and a <> 1');

{ "key": "key2", "value": { "a": 2 } }

TODO

This is a work in progress, and I don't plan to give it a ton of attention, if you like this idea ping me and I will add you as a contributor.