meteor - Meteor：反应式更新，级联删除/更新。规范化与非规范化

Question

如何在现有加入的文档中进行级联删除、更新和响应式更新？比如说我以作者身份加入Posts收藏。我可以对集合执行转换功能以获取作者的用户数据，例如在任何帖子上显示作者。问题是当用户更改他/她时，现有帖子不会反应性地更新作者的。当您删除父文档时，子文档仍然存在。我使用了流行的智能包，例如and，但问题仍然存在。任何专家流星开发可以帮助我吗？谢谢你。Meteor.usersuserId()Postsusernameusernameusernameusernamepublish-compositecollection-helpers

Answer 1

如果你想使用 collection-hooks 来解决这个问题，下面的伪代码应该可以帮助你：

// run only on the server where we have access to the complete dataset
if (Meteor.isServer) {
  Meteor.users.after.update(function (userId, doc, fieldNames, modifier, options) {
    var oldUsername = this.previous.username;
    var newUsername = doc.username;
    // don't bother running this hook if username has not changed
    if (oldUsername !== newUsername) {
      Posts.update({
        // find the user and make sure you don't overselect those that have already been updated
        author: userId, 
        authorUsername: oldUsername
      }, {$set: {
        // set the new username
        authorUsername: newUsername
      }}, {
        // update all documents that match
        multi: true
      })
    }
  }, {fetchPrevious: true});
}