# relations [](https://pub.dartlang.org/packages/angel_relations) [](https://travis-ci.org/angel-dart/relations) Database-agnostic relations between Angel services. ```dart // Authors owning one book app.service('authors').afterAll( relations.hasOne('books', as: 'book', foreignKey: 'authorId')); // Or multiple app.service('authors').afterAll( relations.hasMany('books', foreignKey: 'authorId')); // Or, books belonging to authors app.service('books').afterAll(relations.belongsTo('authors')); ``` Supports: * `hasOne` * `hasMany` * `hasManyThrough` * `belongsTo` * `belongsToMany`