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
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 a JSON file, please make sure it contains a valid JSON array, otherwise diskDB
will return 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.collectionName.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.collectionName.find(query)
- db.collectionName.findOne(query)
db.collectionName.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.
Find can take multiple criteria
var db = require('diskdb');
db.connect('/examples/db', ['articles']);
db.articles.find({rating : "5 stars", published: "yesterday"});
This will return all the articles with a rating of 5, published yesterday.
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.collectionName.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.collectionName.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.collectionName.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.collectionName.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