Embedded JavaScript in-process file system backed database upward compatible on API level with MongoDB.
Upward compatible means that if you build app that uses functionality implemented by TingoDB you can switch to MongoDB almost without code changes. This greatly reduces implementation risks and give you freedom to switch to mature solution at any moment.
As a proof for upward compatibility all tests designed to run against both MongoDB and TingoDB. More over significant part of tests contributed from MongoDB nodejs driver project and used as is without modifications.
For those folks who familiar with Mongoose.js ODM we suggest to look at Tungus, experimental driver that allows to use famous ODM tool with our database.
For more details please visit http://www.tingodb.com
npm install tingodb
As it stated API is fully compatible with MongoDB. Difference is only initialization and obtaining of Db object. Consider this MongoDB code:
var Db = require('mongodb').Db,
Server = require('mongodb').Server,
assert = require('assert');
var db = new Db('test', new Server('locahost', 27017));
var collection = db.collection("batch_document_insert_collection_safe");
collection.insert([{hello:'world_safe1'}
, {hello:'world_safe2'}], {w:1}, function(err, result) {
assert.equal(null, err);
collection.findOne({hello:'world_safe2'}, function(err, item) {
assert.equal(null, err);
assert.equal('world_safe2', item.hello);
})
});
The same example using TingoDB will be following:
var Db = require('tingodb')().Db,
assert = require('assert');
var db = new Db('/some/local/path', {});
// Fetch a collection to insert document into
var collection = db.collection("batch_document_insert_collection_safe");
// Insert a single document
collection.insert([{hello:'world_safe1'}
, {hello:'world_safe2'}], {w:1}, function(err, result) {
assert.equal(null, err);
// Fetch the document
collection.findOne({hello:'world_safe2'}, function(err, item) {
assert.equal(null, err);
assert.equal('world_safe2', item.hello);
})
});
So, as you can see difference is in require call and database object initialization.
In contrast to MongoDB, module require call will not return usable module. It will return a function that accept configuration options. This function will return something similar to MongoDB module. Extra step allows to inject some options that will control database behavior.
Doing some experimentation we found that using integer keys we can get database work faster and save some space. Additionally for in-process database there are almost no any drawbacks versus globally unique keys. However in the same time it is relatively hard to keep unique integer keys outside of the database engine. So we make it part of the database engine code. Generated keys will be unique in collection scope.
When required it is possible to switch to BSON ObjectID using the configuration option.
Maximum number of cached objects per collection.
Maximum size of object that can be placed to cache.
Globally enables support of search in nested array. MongoDB support this unconditionally. For TingoDB search in arrays when there are no arrays is performance penalty. That's why it is switched off by default. Additionally, and it might be better approach, nested arrays support can be enabled for individual indexes or search queries.
To enable nested arrays in individual index use "_tiarr:true" option.
self._cash_transactions.ensureIndex("splits.accountId",{_tiarr:true},cb);
To enable nested arrays in individual query for fields that do not use indexes use "_tiarr." prefixed field names.
coll.find({'arr.num':10},{"_tiar.arr.num":0})
The only required parameter is database path. It should be valid path to empty folder or folder that already contain collection files.
It is possible to build application that will transparently support both MongoDB and TingoDB. Here are some hints that help to do it:
- Wrap module require call into helper module or make it part of core object. This way you can control which engine is loaded in single place.
- Use only native JavaScript types. BSON types can be slow in JavaScript and will need special attention when passed to or from client JavaScript.
- Think about ObjectID as of just unique value that can be converted to and from String regardless its actual meaning.
Please take a look to sample that consists from 3 files.
var fs = require('fs'),db,engine;
// load config
var cfg = JSON.parse(fs.readFileSync("./config.json"));
// load requestd engine and define engine agnostic getDB function
if (cfg.app.engine=="mongodb") {
engine = require("mongodb");
module.exports.getDB = function () {
if (!db) db = new engine.Db(cfg.mongo.db,
new engine.Server(cfg.mongo.host, cfg.mongo.port, cfg.mongo.opts),
{native_parser: false, safe:true});
return db;
}
} else {
engine = require("tingodb")({});
module.exports.getDB = function () {
if (!db) db = new engine.Db(cfg.tingo.path, {});
return db;
}
}
// Depending on engine this can be different class
module.exports.ObjectID = engine.ObjectID;
var engine = require('./engine');
var db = engine.getDB();
console.time("sample")
db.open(function(err,db) {
db.collection("homes", function (err, homes) {
// its fine to create ObjectID in advance
// NOTE!!! we get class thru engine because its type
// can depends on database type
var homeId = new engine.ObjectID();
// but with TingoDB.ObjectID righ here it will be negative
// which means temporary. However its uniq and can be used for
// comparisons
console.log(homeId);
homes.insert({_id:homeId, name:"test"}, function (err, home) {
var home = home[0];
// in this place homeID will change its value and will be in sync
// with database
console.log(homeId,home);
db.collection("rooms", function (err, rooms) {
for (var i=0; i<5; i++) {
// its ok also to not provide id, then it will be
// generated
rooms.insert({name:"room_"+i,_idHome:homeId}, function (err, room) {
console.log(room[0]);
i--;
if (i==0) {
// now lets assume we serving request like
// /rooms?homeid=_some_string_
var query = "/rooms?homeid="+homeId.toString();
// dirty code to get simulated GET variable
var getId = query.match("homeid=(.*)")[1];
console.log(query, getId)
// typical code to get id from external world
// and use it for queries
rooms.find({_idHome:new engine.ObjectID(getId)})
.count(function (err, count) {
console.log(count);
console.timeEnd("sample");
})
}
})
}
})
})
})
})
{
"app":{
"engine":"tingodb"
},
"mongo":{
"host":"127.0.0.1",
"port":27017,
"db":"data",
"opts":{
"auto_reconnect": true,
"safe": true
}
},
"tingo":{
"path":"./data"
}
}
-2
13 { _id: 13, name: 'test' }
{ name: 'room_0', _idHome: 13, _id: 57 }
{ name: 'room_1', _idHome: 13, _id: 58 }
{ name: 'room_2', _idHome: 13, _id: 59 }
{ name: 'room_3', _idHome: 13, _id: 60 }
{ name: 'room_4', _idHome: 13, _id: 61 }
/rooms?homeid=13 13
5
sample: 27ms
51b43a05f092a1c544000001
51b43a05f092a1c544000001 { _id: 51b43a05f092a1c544000001, name: 'test' }
{ name: 'room_3',
_idHome: 51b43a05f092a1c544000001,
_id: 51b43a05f092a1c544000005 }
{ name: 'room_2',
_idHome: 51b43a05f092a1c544000001,
_id: 51b43a05f092a1c544000004 }
{ name: 'room_1',
_idHome: 51b43a05f092a1c544000001,
_id: 51b43a05f092a1c544000003 }
{ name: 'room_0',
_idHome: 51b43a05f092a1c544000001,
_id: 51b43a05f092a1c544000002 }
{ name: 'room_4',
_idHome: 51b43a05f092a1c544000001,
_id: 51b43a05f092a1c544000006 }
/rooms?homeid=51b43a05f092a1c544000001 51b43a05f092a1c544000001
5
sample: 22ms
We maintain full API and functionality compatibility with MongoDB BUT only for what we implemented support. I.e. if we support something it will work exactly the same, but something is not yet supported or support is limited.
- Search, almost all clauses. Indexes are used to increase search speed and sorting.
- Map reduce, almost all
- Grouping, almost all
- Collection, almost all methods
- Cursor, almost all methods
- Indexes, no support for compaund indxes, only single field indexes are supported. Full text search is also not supprted
- GridFS, no support
- Feature X, now know, might be :)
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