ddb

Dynamic Database

A basic graph database

Note: This requires ES6 Collections - Enable them with --harmony-collections

Overview

There are two types of objects (by default):

• Identity Objects -- Purely identity, no state, the id is random
• Data Objects -- Purely data, the id is based on the data

You can register objects into a database and associate two objects together. To get the objects back you can either get all objects of a type or get all associated objects of an object (optionally restricting it to a type).

Usage

DB

• register(Object): Register an object with the database
• assoc(a: Object, b: Object): Associate a with b
• assocs(obj: Object, [kind: Kind]): Get all the objects associated with obj of kind: kind
• all(kind: Kind): Get all objects of kind: kind

Object

• registered(db: DB): Callback for when it's registered with a database
• id(): ID for this object, abstract

Data

• new Data(data...): Create a new data object with data: data

ID

Don't use one of these with multiple databases - only the last one you register it with will work

Example

var ddb = require('ddb')
var util = require('util')

// Create a database
var db = new ddb.DB

// Create a person class of identity
function Person() {
	ddb.ID.call(this)
}
util.inherits(Person, ddb.ID)

// Create a name class of data
function Name() {
	ddb.Data.apply(this, arguments)
}
util.inherits(Name, ddb.Data)

// Create a new person
var johnDoe = new Person
db.register(johnDoe) // and register him with in the db
console.log('John Doe:', johnDoe)

// Create the first name
var firstName = new Name('first', 'John')
db.register(firstName) // register it
db.assoc(johnDoe, firstName) // associate it with John Doe

// Create the last name
var lastName = new Name('last', 'Doe')
db.register(lastName) // register it
db.assoc(johnDoe, lastName) // associate it with John Doe

console.log('John Doe\'s names:', db.assocs(johnDoe, Name))
console.log('People with a last name of Doe:', db.assocs(new Name('last', 'Doe')))