LevelDb examples for ChelaJs #2

01-simple-leveldb.js

var level = require('level');

var db = level('./chelajs-demo');

db.put("foo", "bar", function () {
	console.log("foo has been saved");
});

02-get.js

var level = require('level');

var db = level('./chelajs-demo');

db.get('foo', function(err, foo){
	console.log(err, foo);
});

03-delete.js

var level = require('level');

var db = level('./chelajs-demo');

db.del('foo', function(err, foo){
	console.log('foo has been deleted');

	db.get('foo', function (err, foo) {
		console.log(err, foo);
	});
});

04-batch.js

var level = require('level');

var db = level('./chelajs-demo');

var ops = [
    { type: "del", key: 'foo' },
	{ type: "put", key: "rog3r"        , value : "hitchhiker’s guide to processing.js"},
	{ type: "put", key: "xiam"         , value : "javascript tetris"},
	{ type: "put", key: "jeduan"       , value : "Handlebars"},
	{ type: "put", key: "pateketrueke" , value : "Js en Grupo Expansion"},
	{ type: "put", key: "Siedrix"      , value : "LevelDb"},
	{ type: "put", key: "HardBit"      , value : "Apps Desktop con nodejs y chromium"},
	{ type: "put", key: "JCeb"         , value : "desarrollo de bibliotecas javascript, server side y client side"}
];

db.batch(ops, function (err) {
	if (err) return console.log('Ooops!', err);
	console.log('Yei beer and js!');
});

05-query.js

var level = require('level');

var db = level('./chelajs-demo');

setTimeout(function () {
	db.createReadStream().on('data', function(data){
		console.log("Got:",data);
	})
	.on('end', function(){
		console.log("Finish query");
	})
	.on('error', function(err){
		console.log("There as an error", err);
	});
}, 200);

06-listening-to-db-changes.js

var level = require('level');

level('./chelajs-demo',{createIfMissing: true}, function (err, db) {
	var liveStream = require('level-live-stream')(db);
	liveStream.on('data', function(data){
		if(!data.type) return;
		console.log('Change on:', process.hrtime());
		console.log(data);
		console.log("========================================");
	});

	var ops = [
		{ type: "del", key: 'foo' },
		{ type: "put", key: "rog3r"        , value : "hitchhiker’s guide to processing.js"},
		{ type: "put", key: "xiam"         , value : "javascript tetris"},
		{ type: "put", key: "jeduan"       , value : "Handlebars"},
		{ type: "put", key: "pateketrueke" , value : "Js en Grupo Expansion"},
		{ type: "put", key: "Siedrix"      , value : "LevelDb"},
		{ type: "put", key: "HardBit"      , value : "Apps Desktop con nodejs y chromium"},
		{ type: "put", key: "JCeb"         , value : "desarrollo de bibliotecas javascript, server side y client side"}
	];

	db.batch(ops, function (err) {
		if (err) return console.log('Ooops!', err);
		console.log('Done ==> Yei beer and js!');
	});
});

07-collections.js

var level = require('level');
var Sublevel = require('level-sublevel');

var db = level('./chelajs-demo');
db = Sublevel(db);

var js = db.sublevel('js');
var beer = db.sublevel('beer');

beer.put('foo','qui');
beer.put('bar','quz');

setTimeout(function () {
	js.put('foo','bar', function(err){
		beer.createReadStream().on('data', function(data){
			console.log("Got:",data);
		})
		.on('end', function(){
			console.log("Finish query");
		})
		.on('error', function(err){
			console.log("There as an error", err);
		});
	});
}, 1000);

08-json-values.js

var level = require('level');
var Sublevel = require('level-sublevel');

var db = level('./chelajs-demo', { valueEncoding: 'json' });
db = Sublevel(db);

var sub = db.sublevel('stuff');

sub.put('foo', {bar:true}, function (err) {
	sub.get('foo', function (err, data) {
		console.log(typeof data);
		console.log('foo:', data);
	});
});

links.txt

Links used in the presentation.
http://www.w3.org/TR/IndexedDB/
http://research.google.com/pubs/SanjayGhemawat.html
http://research.google.com/pubs/jeff.html
https://code.google.com/p/leveldb/
http://basho.com/riak/
https://npmjs.org/package/level-sublevel
https://github.com/rvagg/node-levelup/wiki/Modules
https://github.com/eugeneware/jsonquery-engine