我有两个型号：
App.User = DS.Model.create({
comments: DS.hasMany('App.Comment')
});
App.Comment = DS.Model.create({
user: DS.belongsTo('App.User')
});
当用户被删除时,它也会删除其后端的所有注释,所以我应该从客户端身份映射中删除它们.
我从另一个地方列出系统上的所有评论,所以在删除用户之后,它将会崩溃.
有没有办法在协会上指定这种依赖关系？谢谢！
解决方法
当我想实现这个行为时,我使用mixin.我的模型定义如下：
App.Post = DS.Model.extend(App.DeletesDependentRelationships,{
dependentRelationships: ['comments'],comments: DS.hasMany('App.Comment'),author: DS.belongsTo('App.User')
});
App.User = DS.Model.extend();
App.Comment = DS.Model.extend({
post: DS.belongsTo('App.Post')
});
mixin本身：
App.DeletesDependentRelationships = Ember.Mixin.create({
// an array of relationship names to delete
dependentRelationships: null,// set to 'delete' or 'unload' depending on whether or not you want
// to actually send the deletions to the server
deleteMethod: 'unload',deleteRecord: function() {
var transaction = this.get('store').transaction();
transaction.add(this);
this.deleteDependentRelationships(transaction);
this._super();
},deleteDependentRelationships: function(transaction) {
var self = this;
var klass = Ember.get(this.constructor.toString());
var fields = Ember.get(klass,'fields');
this.get('dependentRelationships').forEach(function(name) {
var relationshipType = fields.get(name);
switch(relationshipType) {
case 'belongsTo': return self.deleteBelongsToRelationship(name,transaction);
case 'hasMany': return self.deleteHasManyRelationship(name,transaction);
}
});
},deleteBelongsToRelationship: function(name,transaction) {
var record = this.get(name);
if (record) this.deleteOrUnloadRecord(record,transaction);
},deleteHasManyRelationship: function(key,transaction) {
var self = this;
// deleting from a RecordArray doesn't play well with forEach,// so convert to a normal array first
this.get(key).toArray().forEach(function(record) {
self.deleteOrUnloadRecord(record,transaction);
});
},deleteOrUnloadRecord: function(record,transaction) {
var deleteMethod = this.get('deleteMethod');
if (deleteMethod === 'delete') {
transaction.add(record);
record.deleteRecord();
}
else if (deleteMethod === 'unload') {
var store = this.get('store');
store.unloadRecord(record);
}
}
});
请注意,您可以通过deleteMethod指定是否要将DELETE请求发送到您的API.如果您的后端配置为自动删除相关记录,则需要使用默认值.