Three way relationship

问题

Creating the following relationships

bookmark.belongsToMany(tag, {through: 'BookmarkTag'}); user.belongsToMany(bookmark, {through: 'UserBookmark'});

Will create two relationshiptables

BookmarkTag |bookmarkId|tagId

UserBookmark |bookmarkId|userId

i would like BookmarkTag to contain user id aswell so that i know which user added a tag to which bookmark

BookmarkTag

|bookmarkId|tagId|userId

is that possible through sequelize associations

fullcode

var bookmark = sequelize.define('Bookmark', {
  name: Sequelize.STRING,
  url: Sequelize.STRING
});
var tag = sequelize.define('Tag', {
  value: Sequelize.STRING
});
var user = sequelize.define('User', {
  email: Sequelize.STRING
});
bookmark.belongsToMany(tag, {through: 'BookmarkTag'});
user.belongsToMany(bookmark, {through: 'UserBookmark'});
sequelize.sync();

回答1:

If you define the BookmarkTag table explicitly you can add extra attributes to it:

BookmarkTag = sequelize.define('BookmarkTag', {
    userId: Sequelize.INTEGER
});

bookmark.belongsToMany(tag, {through: BookmarkTag});

Notice that we are passing a reference to the BookmarkTag model, not a string here.

To set a userid on the tag, you pass an extra object when doing addTag

Bookmark.addTag(tag, { userId: 42 });

来源：https://stackoverflow.com/questions/29099956/three-way-relationship