我如何更新hasandbelongstomany关系为多个模型一次在强循环环回

Question

我在Strongloop环回API中有2个模型

产品
• 标记

在这两个模型之间，我定义了一个hasAndBelongsToMany-relation。在我的CMS中，我想为我的产品提供批量更新功能，这样我就可以在一个操作中选择许多产品，并分配许多标签。

我如何轻松地将这些保存到我的Mysql-DB，而不必遍历每个产品，然后遍历每个标签，并链接这两个?

我检查了文档，发现了添加和删除功能，但这些功能只将一个模型连接到一个relatedModel。是否已经有环回功能来做我想要的?

Answer 1

我在一个服务中编写了一个自定义(更新)函数和一个helper:

/*
* Add multiple objects to a relationship
* @param {object} origin The object which hold the items
* @param {array} data The new list to be inserted
* @param {string} relation name of the relationship, for instance 'cats'
*/
exports.updateManyRelations = function(origin, data, relation){
  //Destroy all old connections
  return origin[relation].destroyAll().then(function(response){
    //All were deleted and nothing to add
    if(!data || data.length == 0){return [];}
    //We have a list to go through, do the dirty work!
    return addMultipleRelationsToObject(origin[relation], data, []);
  }).then(function(newList){
    // new items created
    return newList
  }, function(error){
    console.log(error);
  });
}
/*
* Helper function to add multiple related objects to a object in a correct promise chain
*/
var addMultipleRelationsToObject = function(objectRelation, list, newList){
  if(list && list.length == 0){return Promise.resolve(newList);}
  var item = list.pop();
  if(!objectRelation.hasOwnProperty("add")){
    return Promise.reject("Relationship is wrong for: " + objectRelation);
  }
  return objectRelation.add(item.id).then(function(newlyAdded){
    newList.push(item);
    return addMultipleRelationsToObject(objectRelation, list, newList);
  });
}

Answer 2

遗憾的是，还没有批量更新。见https://github.com/strongloop/loopback/issues/1275