使用Sequelize更新关联表数据的工作示例？

Question

This is my model:

 var Vote = sequelize.define('vote', { title: { type: Sequelize.STRING, allowNull: false }, description: { type: Sequelize.TEXT } }); var Choice = sequelize.define('choice', { choiceTitle: { type: Sequelize.STRING, allowNull: false }, count: { type: Sequelize.INTEGER, length: 6 } }); Choice.belongsTo(Vote); Vote.hasMany(Choice, {onUpdate: 'cascade'}); 

Below is the code to update the 'votes' table including associated 'choices' table if possible using 'vote' argument of 'store()' which is already an object of a Vote with updated values including 'choices' from the app.

 store(vote, callback) { return Vote.findById(vote.id, { include: [ { model: Choice, as: 'choices' } ] }).then(function(resVote) { resVote.choices[0].updateAttributes({count: 120}) // just to test if at least it gets written to db .then(function(res) { callback(null, res); }).catch((err) => callback(err, null)); }); }, 

FYI: In the code I just set one attribute of a specific choice to 120, just to see if it gets written down in the postgres-db, and, hooray, that works (thanks to Jan Aagaard's reply on Updating attributes in associated models using Sequelize to at least have an update on associated table).

I did not really find a solution in Sequelize's docs (at least they have some). When I try to 'save()', 'update()' or 'upsert()' vote directly it just creates a completely new row with empty fields if null is allowed, or simply fails if null is disallowed.

What is the recommended way to update all (changed) fields of a table and if possible also an associated table in Sequelize? Sorry if this question is a bit basic, but I'm quite stuck right now and did not find a clear answer for this task.

Answer 1

You can pass an include obj to creates (see under "Creating with associations" on http://sequelize.readthedocs.io/en/v3/docs/associations/ ) but it doesn't look like you can do so with updates.

I think what you want to do is fetch the related record(s) using the relationship accessors Sequelize gives you and update those instances:

 Vote.findById(vote.id)
  .then(function(vote) {
    return vote.getChoices()
  })
  .then(function(choices) {
    return choices[0].update({ count: 120 })
  })
  .then(function(choice) {
    callback(null, choice);
  })
  .catch(function(err) {
    callback(err);
  });

  (I realise this means you lose the join and end up with two separate queries, but I can't think another way of doing this just now)