Hierarchy
Ext.data.AssociationExt.data.BelongsToAssociation
Represents a many to one association with another model. The owner model is expected to have -a foreign key which references the primary key of the associated model:
- - - - -Ext.define('Category', {
- extend: 'Ext.data.Model',
- fields: [
- {name: 'id', type: 'int'},
- {name: 'name', type: 'string'}
- ]
-});
-
-Ext.define('Product', {
- extend: 'Ext.data.Model',
- fields: [
- {name: 'id', type: 'int'},
- {name: 'category_id', type: 'int'},
- {name: 'name', type: 'string'}
- ],
- // we can use the belongsTo shortcut on the model to create a belongsTo association
- belongsTo: {type: 'belongsTo', model: 'Category'}
-});
-In the example above we have created models for Products and Categories, and linked them together -by saying that each Product belongs to a Category. This automatically links each Product to a Category -based on the Product's category_id, and provides new functions on the Product model:
- - - - -Generated getter function
- - - - -The first function that is added to the owner model is a getter function:
- - - - -var product = new Product({
- id: 100,
- category_id: 20,
- name: 'Sneakers'
-});
-
-product.getCategory(function(category, operation) {
- //do something with the category object
- alert(category.get('id')); //alerts 20
-}, this);
-The getCategory function was created on the Product model when we defined the association. This uses the -Category's configured proxy to load the Category asynchronously, calling the provided -callback when it has loaded.
- - - - -The new getCategory function will also accept an object containing success, failure and callback properties -- callback will always be called, success will only be called if the associated model was loaded successfully -and failure will only be called if the associatied model could not be loaded:
- - - - -product.getCategory({
- callback: function(category, operation) {}, //a function that will always be called
- success : function(category, operation) {}, //a function that will only be called if the load succeeded
- failure : function(category, operation) {}, //a function that will only be called if the load did not succeed
- scope : this //optionally pass in a scope object to execute the callbacks in
-});
-In each case above the callbacks are called with two arguments - the associated model instance and the -operation object that was executed to load that instance. The Operation object is -useful when the instance could not be loaded.
- - - - -Generated setter function
- - - - -The second generated function sets the associated model instance - if only a single argument is passed to -the setter then the following two calls are identical:
- - - - -//this call
-product.setCategory(10);
-
-//is equivalent to this call:
-product.set('category_id', 10);
-If we pass in a second argument, the model will be automatically saved and the second argument passed to -the owner model's save method:
- - -product.setCategory(10, function(product, operation) {
- //the product has been saved
- alert(product.get('category_id')); //now alerts 10
-});
-
-//alternative syntax:
-product.setCategory(10, {
- callback: function(product, operation), //a function that will always be called
- success : function(product, operation), //a function that will only be called if the load succeeded
- failure : function(product, operation), //a function that will only be called if the load did not succeed
- scope : this //optionally pass in a scope object to execute the callbacks in
-})
-Customisation
- - - - -Associations reflect on the models they are linking to automatically set up properties such as the -primaryKey and foreignKey. These can alternatively be specified:
- - - - -Ext.define('Product', {
- fields: [...],
-
- associations: [
- {type: 'belongsTo', model: 'Category', primaryKey: 'unique_id', foreignKey: 'cat_id'}
- ]
-});
- Here we replaced the default primary key (defaults to 'id') and foreign key (calculated as 'category_id') -with our own settings. Usually this will not be needed.
- -The string name of the model that is being associated with. Required
-The string name of the model that is being associated with. Required
-The name of the property in the data to read the association from. -Defaults to the name of the associated model.
-The name of the property in the data to read the association from. -Defaults to the name of the associated model.
-The name of the foreign key on the owner model that links it to the associated -model. Defaults to the lowercased name of the associated model plus "_id", e.g. an association with a -model called Product would set up a product_id foreign key.
- -Ext.define('Order', {
- extend: 'Ext.data.Model',
- fields: ['id', 'date'],
- hasMany: 'Product'
-});
-
-Ext.define('Product', {
- extend: 'Ext.data.Model',
- fields: ['id', 'name', 'order_id'], // refers to the id of the order that this product belongs to
- belongsTo: 'Group'
-});
-var product = new Product({
- id: 1,
- name: 'Product 1',
- order_id: 22
-}, 1);
-product.getOrder(); // Will make a call to the server asking for order_id 22
-
-The name of the getter function that will be added to the local model's prototype. -Defaults to 'get' + the name of the foreign model, e.g. getCategory
-The string name of the model that owns the association. Required
-The string name of the model that owns the association. Required
-The name of the primary key on the associated model. Defaults to 'id'. -In general this will be the Ext.data.Model.idProperty of the Model.
-The name of the setter function that will be added to the local model's prototype. -Defaults to 'set' + the name of the foreign model, e.g. setCategory
-The type configuration can be used when creating associations using a configuration object. -Use 'belongsTo' to create a HasManyAssocation
- -associations: [{
- type: 'belongsTo',
- model: 'User'
-}]
-The name of the model is on the other end of the association (e.g. if a User model hasMany Orders, this is 'Order')
-The name of the model is on the other end of the association (e.g. if a User model hasMany Orders, this is 'Order')
-