module.exports = {
  attributes: {
    person:{
      model:'person'
    },
    book: {
      model: 'book'
    },
    purpose: {
      type: 'string'
    },
    sortOrder: {
      type: 'number'
    }
  },

  checkConsistency: async () => {
    var relations = await PersonBook.find().populate('person').populate('book');
    relations = relations
      .filter(relation => relation.person==null || relation.book==null)
      .map(relation => relation.id);
    await PersonBook.destroy({id: relations});
  }
}