diskDB

A Lightweight Disk based JSON Database with a MongoDB like API for Node.

You will never know that you are interacting with a File System

##Contents

Getting Started
Documentation
- Connect
- Load Collections
- Write/Save
- Read
- Update
- Remove
- Count
Examples
Performance
Contributing
Release History

Getting Started

Install the module locally :

$ npm install diskdb

var db = require('diskdb');
db = db.connect('/path/to/db-folder', ['collection-name']);
// you can access the traditional JSON DB methods here

Documentation

Connect to DB

db.connect(pathToFolder, ['filename']);

Filename will be the name of the JSON file. You can omit the extension, diskDB will take care of it for you.

var db = require('diskdb');
db = db.connect('/examples/db', ['articles']);
// or simply
db.connect('/examples/db', ['articles']);

This will check for a directory at given path, if it does not exits, diskDB will throw an error and exit.

If the directory exists but the file/collection does not exist, diskDB will create it for you.

Note : If you have manually created an empty JSON file, please make sure that it contains at least an empty array.

[]

Else it will throw an error like

undefined:0

^
SyntaxError: Unexpected end of input

Load Collections

Alternatively you can also load collections like

var db = require('diskdb');
// this
db = db.connect('/examples/db');
db.loadCollections(['articles']);
//or
db.connect('/examples/db');
db.loadCollections(['articles']);
//or
db.connect('/examples/db')
  .loadCollections(['articles']);
//or
db.connect('/examples/db', ['articles']);

Load Multiple Collections

var db = require('diskdb');
db.connect('/examples/db', ['articles','comments','users']);

Write/Save to Collection

db.collectioName.save(object);

Once you have loaded a collection, you can access the collection's methods using the dot notation like

db.[collectionName].[methodname]

To save the data, you can use

var db = require('diskdb');
db.connect('db', ['articles']);
var article = {
    title : "diskDB rocks",
    published : "today",
    rating : "5 stars"
}
db.articles.save(article);
// or
db.articles.save([article]);

The saved data will be

[
    {
        "title": "diskDB rocks",
        "published": "today",
        "rating": "5 stars",
        "_id": "0f6047c6c69149f0be0c8f5943be91be"
    }
]

You can also save multiple objects at once like

var db = require('diskdb');
db.connect('db', ['articles']);
var article1 = {
    title : 'diskDB rocks',
    published : 'today',
    rating : '5 stars'
}

var article2 = {
    title : 'diskDB rocks',
    published : 'yesterday',
    rating : '5 stars'
}

var article3 = {
    title : 'diskDB rocks',
    published : 'today',
    rating : '4 stars'
}
db.articles.save([article1, article2, article3]);

And this will return the inserted objects

[ { title: 'diskDB rocks',
    published: 'today',
    rating: '4 stars',
    _id: 'b1cdbb3525b84e8c822fc78896d0ca7b' },
  { title: 'diskDB rocks',
    published: 'yesterday',
    rating: '5 stars',
    _id: '42997c62e1714e9f9d88bf3b87901f3b' },
  { title: 'diskDB rocks',
    published: 'today',
    rating: '5 stars',
    _id: '4ca1c1597ddc4020bc41b4418e7a568e' } ]

Read from Collection

There are 2 methods available for reading the JSON collection

db.collectioName.find(query)
db.collectioName.findOne(query)

db.collectioName.find()

var db = require('diskdb');
db.connect('/examples/db', ['articles']);
db.articles.find();

This will return all the records

[{ 
    title: 'diskDB rocks',
    published: 'today',
    rating: '5 stars',
    _id: '0f6047c6c69149f0be0c8f5943be91be' 
}]

You can also query with a criteria like

var db = require('diskdb');
db.connect('/examples/db', ['articles']);
db.articles.find({rating : "5 stars"});

This will return all the articles which have a rating of 5.

Nested JSON :

var articleComments = {
    title: 'diskDB rocks',
    published: '2 days ago',
    comments: [{
        name: 'a user',
        comment: 'this is cool',
        rating: 2
    }, {
        name: 'b user',
        comment: 'this is ratchet',
        rating: 3
    }, {
        name: 'c user',
        comment: 'this is awesome',
        rating: 2
    }]
}

var savedArticle = db.articles.save([articleComments);
foundArticles = db.articles.find({rating : 2});

Since diskDB is mostly for light weight data storage, avoid nested structures and huge datasets.

db.collectioName.findOne(query)

var db = require('diskdb');
db.connect('/examples/db', ['articles']);
db.articles.findOne();

If you do not pass a query, diskDB will return the first article in the collection. If you pass a query, it will return first article in the filtered data.

var db = require('diskdb');
db.connect('/examples/db', ['articles']);
db.articles.findOne({_id: '0f6047c6c69149f0be0c8f5943be91be'});

Update Collection

db.collectioName.update(query, data, options);

You can also update one or many objects in the collection

options = {
    multi: false, // update multiple - default false
    upsert: false // if object is not found, add it (update-insert) - default false
}

Usage

var db = require('diskdb');
db.connect('/examples/db', ['articles']);

var query = {
  title : 'diskDB rocks'
};

var dataToBeUpdate = {
  title : 'diskDB rocks again!',
};

var options = {
   multi: false,
   upsert: false
};

var updated = db.articles.update(query, dataToBeUpdate, options);
console.log(updated); // { updated: 1, inserted: 0 }

Remove Collection

db.collectioName.remove(query, multi);

You can remove the entire collection (including the file) or you can remove the matched objects by passing in a query. When you pass a query, you can either delete all the matched objects or only the first one by passing multi as false. The default value of multi is true.

var db = require('diskdb');
db.connect('/examples/db', ['articles']);
db.articles.remove({rating : "5 stars"});

var db = require('diskdb');
db.connect('/examples/db', ['articles']);
db.articles.remove({rating : "5 stars"}, true); // remove all matched. Default - multi = true

var db = require('diskdb');
db.connect('/examples/db', ['articles']);
db.articles.remove({rating : "5 stars"}, false); // remove only the first match

Using remove without any params will delete the file and will remove the db instance.

var db = require('diskdb');
db.connect('/examples/db', ['articles']);
db.articles.remove();

After the above operation db.articles is undefined.

Count

db.collectioName.count();

Will return the count of objects in the Collection

var db = require('diskdb');
db.connect('/examples/db', ['articles']);
db.articles.count(); // will give the count

Examples

Refer to the examples folder.

Performance

To validate diskDB's performance and to check if it meets your needs, you can clone this repo and run

$ node performance/time.js

An average of few tests (run on OS X - 10.9.3 | 2.9GHZ i7 | 8GB 1600MHz DDR3) can be found below

Time taken to process x number of objects (in ms) vs Action Performed

	1 (object)	1000 (objects)	10000 (objects)	100000 (objects)	1000000 (objects)
Save	1 (ms)	15 (ms)	137 (ms)	1782 (ms)	14425 (ms)
Find all without query	0 (ms)	2 (ms)	12 (ms)	204 (ms)	2923 (ms)
Find all with query	0 (ms)	2 (ms)	17 (ms)	738 (ms)	1985 (ms)
Find one without query	0 (ms)	1 (ms)	9 (ms)	791 (ms)	1676 (ms)
Find one with query	0 (ms)	1 (ms)	8 (ms)	219 (ms)	1410 (ms)
Update all records	1 (ms)	7 (ms)	61 (ms)	206 (ms)	48035 (ms)
Get count	0 (ms)	3 (ms)	11 (ms)	260 (ms)	2420 (ms)
Remove with query	0 (ms)	7 (ms)	59 (ms)	984 (ms)	48191 (ms)
Remove collection	0 (ms)	1 (ms)	4 (ms)	52 (ms)	154 (ms)
File size	0.000111 (MB)	0.116671 (MB)	1.196671 (MB)	12.266671 (MB)	125.666671 (MB)

Contributing

See the CONTRIBUTING Guidelines

Release History

0.1.x
- Base Module with
  - Connect to a Folder
  - Access a Collection/File
  - Create Read Update Delete on JSON object
  - Minor fixes and tests
  - Performance improvements

samsel/diskDB