loopback-datasource-juggler/README.md

About

JugglingDB is cross-db ORM, providing common interface to access most popular database formats. Currently supported are: mysql, mongodb, redis, neo4j and js-memory-storage (yep, self-written engine for test-usage only). You can add your favorite database adapter, checkout one of the existing adapters to learn how, it's super-easy, I guarantee.

Installation

git clone git://github.com/1602/jugglingdb.git

Usage

var Schema = require('./jugglingdb').Schema;
var s = new Schema('redis');
// define models
var Post = schema.define('Post', {
    title:     { type: String, length: 255 },
    content:   { type: Schema.Text },
    date:      { type: Date,    default: Date.now },
    published: { type: Boolean, default: false }
});
// simplier way to describe model
var User = schema.define('User', {
    name:         String,
    bio:          Schema.Text,
    approved:     Boolean,
    joinedAt:     Date,
    age:          Number
});

// setup relationships
User.hasMany(Post,   {as: 'posts',  foreignKey: 'userId'});
// creates instance methods:
// user.posts(conds)
// user.posts.build(data) // like new Post({userId: user.id});
// user.posts.create(data) // build and save

Post.belongsTo(User, {as: 'author', foreignKey: 'userId'});
// creates instance methods:
// post.author(callback) -- getter when called with function
// post.author() -- sync getter when called without params
// post.author(user) -- setter when called with object

s.automigrate(); // required only for mysql NOTE: it will drop User and Post tables

// work with models:
var user = new User;
user.save(function (err) {
    var post = user.posts.build({title: 'Hello world'});
    post.save(console.log);
});

// Common API methods

// just instantiate model
new Post
// save model (of course async)
Post.create(cb);
// all posts
Post.all(cb)
// all posts by user
Post.all({where: {userId: user.id}});
// the same as prev
user.posts(cb)
// same as new Post({userId: user.id});
user.posts.build
// save as Post.create({userId: user.id}, cb);
user.posts.create(cb)
// find instance by id
User.find(1, cb)
// count instances
User.count(cb)
// destroy instance
user.destroy(cb);
// destroy all instances
User.destroyAll(cb);

// Setup validations
User.validatesPresenceOf('name', 'email')
User.validatesLengthOf('password', {min: 5, message: {min: 'Password is too short'}});
User.validatesInclusionOf('gender', {in: ['male', 'female']});
User.validatesExclusionOf('domain', {in: ['www', 'billing', 'admin']});
User.validatesNumericalityOf('age', {int: true});
User.validatesUniquenessOf('email', {message: 'email is not unique'});

user.isValid(function (valid) {
    if (!valid) {
        user.errors // hash of errors {attr: [errmessage, errmessage, ...], attr: ...}    
    }
})

Callbacks

The following callbacks supported:

- afterInitialize
- beforeCreate
- afterCreate
- beforeSave
- afterSave
- beforeUpdate
- afterUpdate
- beforeDestroy
- afterDestroy
- beforeValidation
- afterValidation

Each callback is class method of the model, it should accept single argument: next, this is callback which should be called after end of the hook. Except afterInitialize because this method is syncronous (called after new Model).

Object lifecycle:

var user = new User;
// afterInitialize
user.save(callback);
// beforeValidation
// afterValidation
// beforeSave
// beforeCreate
// afterCreate
// afterSave
// callback
user.updateAttribute('email', 'email@example.com', callback);
// beforeValidation
// afterValidation
// beforeUpdate
// afterUpdate
// callback
user.destroy(callback);
// beforeDestroy
// afterDestroy
// callback
User.create(data, callback);
// beforeValidate
// afterValidate
// beforeCreate
// afterCreate
// callback

Read the tests for usage examples: ./test/common_test.js Validations: ./test/validations_test.js

Your own database adapter

To use custom adapter, pass it's package name as first argument to Schema constructor:

mySchema = new Schema('couch-db-adapter', {host:.., port:...});

Make sure, your adapter can be required (just put it into ./node_modules):

require('couch-db-adapter');

Running tests

All tests are written using nodeunit:

nodeunit test/common_test.js

If you run this line, of course it will fall, because it requres different databases to be up and running, but you can use js-memory-engine out of box! Specify ONLY env var:

ONLY=memory nodeunit test/common_test.js

of course, if you have redis running, you can run

ONLY=redis nodeunit test/common_test.js

Package structure

Now all common logic described in ./lib/*.js, and database-specific stuff in ./lib/adapters/*.js. It's super-tiny, right?

Project status

This project was written in one weekend (1,2 oct 2011), and of course does not claim to be production-ready, but I plan to use this project as default ORM for RailwayJS in nearest future. So, if you are familiar with some database engines - please help me to improve adapter for that database.

For example, I know, mysql implementation sucks now, 'cause I'm not digging too deep into SequelizeJS code, and I think it would be better to replace sequelize with something low-level in nearest future, such as mysql package from npm.

Contributing

If you have found a bug please write unit test, and make sure all other tests still pass before pushing code to repo.

Roadmap

Common:

• transparent interface to APIs
• -before and -after hooks on save, update, destroy
• scopes
• default values
• more relationships stuff
• docs

Databases:

• riak
• couchdb
• low-level mysql
• postgres
• sqlite

License

MIT