Represents a one-to-many relationship between two models. Usually created indirectly via a model definition:
*
Ext.define('Product', {
extend: 'Ext.data.Model',
fields: [
{name: 'id', type: 'int'},
{name: 'user_id', type: 'int'},
{name: 'name', type: 'string'}
]
});
Ext.define('User', {
extend: 'Ext.data.Model',
fields: [
{name: 'id', type: 'int'},
{name: 'name', type: 'string'}
],
// we can use the hasMany shortcut on the model to create a hasMany association
hasMany: {model: 'Product', name: 'products'}
});
Above we created Product and User models, and linked them by saying that a User hasMany Products. This gives * us a new function on every User instance, in this case the function is called 'products' because that is the name * we specified in the association configuration above.
* *This new function returns a specialized {@link Ext.data.Store Store} which is automatically filtered to load * only Products for the given model instance:
*
//first, we load up a User with id of 1
var user = Ext.create('User', {id: 1, name: 'Ed'});
//the user.products function was created automatically by the association and returns a {@link Ext.data.Store Store}
//the created store is automatically scoped to the set of Products for the User with id of 1
var products = user.products();
//we still have all of the usual Store functions, for example it's easy to add a Product for this User
products.add({
name: 'Another Product'
});
//saves the changes to the store - this automatically sets the new Product's user_id to 1 before saving
products.sync();
The new Store is only instantiated the first time you call products() to conserve memory and processing time, * though calling products() a second time returns the same store instance.
* *Custom filtering
* *The Store is automatically furnished with a filter - by default this filter tells the store to only return * records where the associated model's foreign key matches the owner model's primary key. For example, if a User * with ID = 100 hasMany Products, the filter loads only Products with user_id == 100.
* *Sometimes we want to filter by another field - for example in the case of a Twitter search application we may * have models for Search and Tweet:
*
Ext.define('Search', {
extend: 'Ext.data.Model',
fields: [
'id', 'query'
],
hasMany: {
model: 'Tweet',
name : 'tweets',
filterProperty: 'query'
}
});
Ext.define('Tweet', {
extend: 'Ext.data.Model',
fields: [
'id', 'text', 'from_user'
]
});
//returns a Store filtered by the filterProperty
var store = new Search({query: 'Sencha Touch'}).tweets();
The tweets association above is filtered by the query property by setting the {@link #filterProperty}, and is * equivalent to this:
*
var store = Ext.create('Ext.data.Store', {
model: 'Tweet',
filters: [
{
property: 'query',
value : 'Sencha Touch'
}
]
});
Ext.define('Group', {
extend: 'Ext.data.Model',
fields: ['id', 'name'],
hasMany: 'User'
});
Ext.define('User', {
extend: 'Ext.data.Model',
fields: ['id', 'name', 'group_id'], // refers to the id of the group that this user belongs to
belongsTo: 'Group'
});
*
// This will create a users() method on any Group model instance
Ext.define('Group', {
extend: 'Ext.data.Model',
fields: ['id', 'name'],
hasMany: 'User'
});
var group = new Group();
console.log(group.users());
// The method to retrieve the users will now be getUserList
Ext.define('Group', {
extend: 'Ext.data.Model',
fields: ['id', 'name'],
hasMany: {model: 'User', name: 'getUserList'}
});
var group = new Group();
console.log(group.getUserList());
*
associations: [{
type: 'hasMany',
model: 'User'
}]
*