DS Namespace packages/ember-data/lib/core.js:5

DS.attr defines an attribute on a DS.Model. By default, attributes are passed through as-is, however you can specify an optional type to have the value automatically transformed. Ember Data ships with four basic transform types: string, number, boolean and date. You can define your own transforms by subclassing DS.Transform.

DS.attr takes an optional hash as a second parameter, currently supported options are:

• defaultValue: Pass a string or a function to be called to set the attribute to a default value if none is supplied.

Example

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var attr = DS.attr;

App.User = DS.Model.extend({
  username: attr('string'),
  email: attr('string'),
  verified: attr('boolean', {defaultValue: false})
});

DS.belongsTo is used to define One-To-One and One-To-Many relationships on a DS.Model.

DS.belongsTo takes an optional hash as a second parameter, currently supported options are:

• async: A boolean value used to explicitly declare this to be an async relationship.
• inverse: A string used to identify the inverse property on a related model in a One-To-Many relationship. See Explicit Inverses

One-To-One

To declare a one-to-one relationship between two models, use DS.belongsTo:

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App.User = DS.Model.extend({
  profile: DS.belongsTo('profile')
});

App.Profile = DS.Model.extend({
  user: DS.belongsTo('user')
});

One-To-Many

To declare a one-to-many relationship between two models, use DS.belongsTo in combination with DS.hasMany, like this:

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App.Post = DS.Model.extend({
  comments: DS.hasMany('comment')
});

App.Comment = DS.Model.extend({
  post: DS.belongsTo('post')
});

DS.hasMany is used to define One-To-Many and Many-To-Many relationships on a DS.Model.

DS.hasMany takes an optional hash as a second parameter, currently supported options are:

• async: A boolean value used to explicitly declare this to be an async relationship.
• inverse: A string used to identify the inverse property on a related model.

One-To-Many

To declare a one-to-many relationship between two models, use DS.belongsTo in combination with DS.hasMany, like this:

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App.Post = DS.Model.extend({
  comments: DS.hasMany('comment')
});

App.Comment = DS.Model.extend({
  post: DS.belongsTo('post')
});

Many-To-Many

To declare a many-to-many relationship between two models, use DS.hasMany:

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App.Post = DS.Model.extend({
  tags: DS.hasMany('tag')
});

App.Tag = DS.Model.extend({
  posts: DS.hasMany('post')
});

Explicit Inverses

Ember Data will do its best to discover which relationships map to one another. In the one-to-many code above, for example, Ember Data can figure out that changing the comments relationship should update the post relationship on the inverse because post is the only relationship to that model.

However, sometimes you may have multiple belongsTo/hasManys for the same type. You can specify which property on the related model is the inverse using DS.hasMany's inverse option:

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var belongsTo = DS.belongsTo,
    hasMany = DS.hasMany;

App.Comment = DS.Model.extend({
  onePost: belongsTo('post'),
  twoPost: belongsTo('post'),
  redPost: belongsTo('post'),
  bluePost: belongsTo('post')
});

App.Post = DS.Model.extend({
  comments: hasMany('comment', {
    inverse: 'redPost'
  })
});

You can also specify an inverse on a belongsTo, which works how you'd expect.