Associations enable you to express relationships between different {@link Ext.data.Model Models}. Let's say we're + * writing an ecommerce system where Users can make Orders - there's a relationship between these Models that we can + * express like this:
+ * +
+Ext.define('User', {
+ extend: 'Ext.data.Model',
+ fields: ['id', 'name', 'email'],
+
+ hasMany: {model: 'Order', name: 'orders'}
+});
+
+Ext.define('Order', {
+ extend: 'Ext.data.Model',
+ fields: ['id', 'user_id', 'status', 'price'],
+
+ belongsTo: 'User'
+});
+We've set up two models - User and Order - and told them about each other. You can set up as many associations on + * each Model as you need using the two default types - {@link Ext.data.HasManyAssociation hasMany} and + * {@link Ext.data.BelongsToAssociation belongsTo}. There's much more detail on the usage of each of those inside their + * documentation pages. If you're not familiar with Models already, {@link Ext.data.Model there is plenty on those too}.
+ * + *Further Reading
+ * + *We can also have models that create parent/child associations between the same type. Below is an example, where + * groups can be nested inside other groups:
+ *
+
+// Server Data
+{
+ "groups": {
+ "id": 10,
+ "parent_id": 100,
+ "name": "Main Group",
+ "parent_group": {
+ "id": 100,
+ "parent_id": null,
+ "name": "Parent Group"
+ },
+ "child_groups": [{
+ "id": 2,
+ "parent_id": 10,
+ "name": "Child Group 1"
+ },{
+ "id": 3,
+ "parent_id": 10,
+ "name": "Child Group 2"
+ },{
+ "id": 4,
+ "parent_id": 10,
+ "name": "Child Group 3"
+ }]
+ }
+}
+
+// Client code
+Ext.define('Group', {
+ extend: 'Ext.data.Model',
+ fields: ['id', 'parent_id', 'name'],
+ proxy: {
+ type: 'ajax',
+ url: 'data.json',
+ reader: {
+ type: 'json',
+ root: 'groups'
+ }
+ },
+ associations: [{
+ type: 'hasMany',
+ model: 'Group',
+ primaryKey: 'id',
+ foreignKey: 'parent_id',
+ autoLoad: true,
+ associationKey: 'child_groups' // read child data from child_groups
+ }, {
+ type: 'belongsTo',
+ model: 'Group',
+ primaryKey: 'id',
+ foreignKey: 'parent_id',
+ autoLoad: true,
+ associationKey: 'parent_group' // read parent data from parent_group
+ }]
+});
+
+
+Ext.onReady(function(){
+
+ Group.load(10, {
+ success: function(group){
+ console.log(group.getGroup().get('name'));
+
+ group.groups().each(function(rec){
+ console.log(rec.get('name'));
+ });
+ }
+ });
+
+});
+ *