How To Disambiguate Between Multiple Associations Between The Same Models In Sequelize

I have three models — Book, User and Institution — which are associated to one another as follows: Books are associated to Institutions via a Book_Institution join table (many

Solution 1:

I use as which allows you to reference the relationship through that alias.

Institution.belongsToMany(models.User, { 
    through: 'Author_Institution', // many-to-many relationship table nameas: 'AuthorInstitution'// alias
})

With your models set up this way, you can use as to to specify which relationship you want to include when querying.

getBooks:(obj,args,context)=> {
  const { user } =contextreturnBook.findAll({
    attributes: ['id', 'path'],
    include: [{
      include: [{
        attributes: ['id'],
        model:User,
        where: { id:user },
        as:'AuthorInstitution'
      }],
      model:Institution,
      required:true//innerjoin
    }]
  })
}

Also, with this methodology, it allows you you to reference the relationship data via the as, so you can do book.AuthorInstitution and it will be the value of that object.