diff --git a/packages/relations/.gitignore b/packages/relations/.gitignore
new file mode 100644
index 00000000..e822a056
--- /dev/null
+++ b/packages/relations/.gitignore
@@ -0,0 +1,93 @@
+# See https://www.dartlang.org/tools/private-files.html
+
+# Files and directories created by pub
+.buildlog
+.packages
+.project
+.pub/
+.scripts-bin/
+build/
+**/packages/
+
+# Files created by dart2js
+# (Most Dart developers will use pub build to compile Dart, use/modify these 
+#  rules if you intend to use dart2js directly
+#  Convention is to use extension '.dart.js' for Dart compiled to Javascript to
+#  differentiate from explicit Javascript files)
+*.dart.js
+*.part.js
+*.js.deps
+*.js.map
+*.info.json
+
+# Directory created by dartdoc
+doc/api/
+
+# Don't commit pubspec lock file 
+# (Library packages only! Remove pattern if developing an application package)
+pubspec.lock
+### Dart template
+# See https://www.dartlang.org/tools/private-files.html
+
+# Files and directories created by pub
+
+# SDK 1.20 and later (no longer creates packages directories)
+
+# Older SDK versions
+# (Include if the minimum SDK version specified in pubsepc.yaml is earlier than 1.20)
+
+
+# Files created by dart2js
+# (Most Dart developers will use pub build to compile Dart, use/modify these
+#  rules if you intend to use dart2js directly
+#  Convention is to use extension '.dart.js' for Dart compiled to Javascript to
+#  differentiate from explicit Javascript files)
+
+# Directory created by dartdoc
+
+# Don't commit pubspec lock file
+# (Library packages only! Remove pattern if developing an application package)
+### JetBrains template
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio and Webstorm
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff:
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/dictionaries
+
+# Sensitive or high-churn files:
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.xml
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+
+# Gradle:
+.idea/**/gradle.xml
+.idea/**/libraries
+
+# Mongo Explorer plugin:
+.idea/**/mongoSettings.xml
+
+## File-based project format:
+*.iws
+
+## Plugin-specific files:
+
+# IntelliJ
+/out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
diff --git a/packages/relations/.travis.yml b/packages/relations/.travis.yml
new file mode 100644
index 00000000..de2210c9
--- /dev/null
+++ b/packages/relations/.travis.yml
@@ -0,0 +1 @@
+language: dart
\ No newline at end of file
diff --git a/packages/relations/LICENSE b/packages/relations/LICENSE
new file mode 100644
index 00000000..89074fd3
--- /dev/null
+++ b/packages/relations/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2017 The Angel Framework
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/packages/relations/README.md b/packages/relations/README.md
new file mode 100644
index 00000000..ea8a4e74
--- /dev/null
+++ b/packages/relations/README.md
@@ -0,0 +1,25 @@
+# relations
+[![version 1.0.1](https://img.shields.io/badge/pub-v1.0.1-brightgreen.svg)](https://pub.dartlang.org/packages/angel_relations)
+[![build status](https://travis-ci.org/angel-dart/relations.svg)](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`
\ No newline at end of file
diff --git a/packages/relations/lib/angel_relations.dart b/packages/relations/lib/angel_relations.dart
new file mode 100644
index 00000000..5f2b6a7e
--- /dev/null
+++ b/packages/relations/lib/angel_relations.dart
@@ -0,0 +1,9 @@
+/// Hooks to populate data returned from services, in a fashion
+/// reminiscent of a relational database.
+library angel_relations;
+
+export 'src/belongs_to_many.dart';
+export 'src/belongs_to.dart';
+export 'src/has_many.dart';
+export 'src/has_many_through.dart';
+export 'src/has_one.dart';
\ No newline at end of file
diff --git a/packages/relations/lib/src/belongs_to.dart b/packages/relations/lib/src/belongs_to.dart
new file mode 100644
index 00000000..68ae9c38
--- /dev/null
+++ b/packages/relations/lib/src/belongs_to.dart
@@ -0,0 +1,78 @@
+import 'dart:async';
+import 'dart:mirrors';
+import 'package:angel_framework/angel_framework.dart';
+import 'plural.dart' as pluralize;
+import 'no_service.dart';
+
+/// Represents a relationship in which the current [service] "belongs to"
+/// a single member of the service at [servicePath]. Use [as] to set the name
+/// on the target object.
+///
+/// Defaults:
+/// * [localKey]: `userId`
+/// * [foreignKey]: `id`
+HookedServiceEventListener belongsTo(Pattern servicePath,
+    {String as,
+    String foreignKey,
+    String localKey,
+    getForeignKey(obj),
+    assignForeignObject(foreign, obj)}) {
+  String localId = localKey;
+  var foreignName =
+      as?.isNotEmpty == true ? as : pluralize.singular(servicePath.toString());
+
+  if (localId == null) {
+    localId = foreignName + 'Id';
+    // print('No local key provided for belongsTo, defaulting to \'$localId\'.');
+  }
+
+  return (HookedServiceEvent e) async {
+    var ref = e.service.app.service(servicePath);
+    if (ref == null) throw noService(servicePath);
+
+    _getForeignKey(obj) {
+      if (getForeignKey != null)
+        return getForeignKey(obj);
+      else if (obj is Map)
+        return obj[localId];
+      else if (obj is Extensible)
+        return obj.properties[localId];
+      else if (localId == null || localId == 'userId')
+        return obj.userId;
+      else
+        return reflect(obj).getField(new Symbol(localId)).reflectee;
+    }
+
+    _assignForeignObject(foreign, obj) {
+      if (assignForeignObject != null)
+        return assignForeignObject(foreign, obj);
+      else if (obj is Map)
+        obj[foreignName] = foreign;
+      else if (obj is Extensible)
+        obj.properties[foreignName] = foreign;
+      else
+        reflect(obj).setField(new Symbol(foreignName), foreign);
+    }
+
+    _normalize(obj) async {
+      if (obj != null) {
+        var id = await _getForeignKey(obj);
+        var indexed = await ref.index({
+          'query': {foreignKey ?? 'id': id}
+        });
+
+        if (indexed == null || indexed is! List || indexed.isNotEmpty != true) {
+          await _assignForeignObject(null, obj);
+        } else {
+          var child = indexed.first;
+          await _assignForeignObject(child, obj);
+        }
+      }
+    }
+
+    if (e.result is Iterable) {
+      await Future.wait(e.result.map(_normalize));
+    } else
+      await _normalize(e.result);
+  };
+}
diff --git a/packages/relations/lib/src/belongs_to_many.dart b/packages/relations/lib/src/belongs_to_many.dart
new file mode 100644
index 00000000..2b3a508a
--- /dev/null
+++ b/packages/relations/lib/src/belongs_to_many.dart
@@ -0,0 +1,78 @@
+import 'dart:async';
+import 'dart:mirrors';
+import 'package:angel_framework/angel_framework.dart';
+import 'plural.dart' as pluralize;
+import 'no_service.dart';
+
+/// Represents a relationship in which the current [service] "belongs to"
+/// multiple members of the service at [servicePath]. Use [as] to set the name
+/// on the target object.
+///
+/// Defaults:
+/// * [foreignKey]: `userId`
+/// * [localKey]: `id`
+HookedServiceEventListener belongsToMany(Pattern servicePath,
+    {String as,
+    String foreignKey,
+    String localKey,
+    getForeignKey(obj),
+    assignForeignObject(List foreign, obj)}) {
+  String localId = localKey;
+  var foreignName =
+      as?.isNotEmpty == true ? as : pluralize.plural(servicePath.toString());
+
+  if (localId == null) {
+    localId = foreignName + 'Id';
+    // print('No local key provided for belongsToMany, defaulting to \'$localId\'.');
+  }
+
+  return (HookedServiceEvent e) async {
+    var ref = e.service.app.service(servicePath);
+    if (ref == null) throw noService(servicePath);
+
+    _getForeignKey(obj) {
+      if (getForeignKey != null)
+        return getForeignKey(obj);
+      else if (obj is Map)
+        return obj[localId];
+      else if (obj is Extensible)
+        return obj.properties[localId];
+      else if (localId == null || localId == 'userId')
+        return obj.userId;
+      else
+        return reflect(obj).getField(new Symbol(localId)).reflectee;
+    }
+
+    _assignForeignObject(foreign, obj) {
+      if (assignForeignObject != null)
+        return assignForeignObject(foreign, obj);
+      else if (obj is Map)
+        obj[foreignName] = foreign;
+      else if (obj is Extensible)
+        obj.properties[foreignName] = foreign;
+      else
+        reflect(obj).setField(new Symbol(foreignName), foreign);
+    }
+
+    _normalize(obj) async {
+      if (obj != null) {
+        var id = await _getForeignKey(obj);
+        var indexed = await ref.index({
+          'query': {foreignKey ?? 'id': id}
+        });
+
+        if (indexed == null || indexed is! List || indexed.isNotEmpty != true) {
+          await _assignForeignObject(null, obj);
+        } else {
+          var child = indexed is Iterable ? indexed.toList() : [indexed];
+          await _assignForeignObject(child, obj);
+        }
+      }
+    }
+
+    if (e.result is Iterable) {
+      await Future.wait(e.result.map(_normalize));
+    } else
+      await _normalize(e.result);
+  };
+}
diff --git a/packages/relations/lib/src/has_many.dart b/packages/relations/lib/src/has_many.dart
new file mode 100644
index 00000000..34cffcff
--- /dev/null
+++ b/packages/relations/lib/src/has_many.dart
@@ -0,0 +1,71 @@
+import 'dart:async';
+import 'dart:mirrors';
+import 'package:angel_framework/angel_framework.dart';
+import 'plural.dart' as pluralize;
+import 'no_service.dart';
+
+/// Represents a relationship in which the current [service] "owns"
+/// members of the service at [servicePath]. Use [as] to set the name
+/// on the target object.
+///
+/// Defaults:
+/// * [foreignKey]: `userId`
+/// * [localKey]: `id`
+HookedServiceEventListener hasMany(Pattern servicePath,
+    {String as,
+    String foreignKey,
+    String localKey,
+    getLocalKey(obj),
+    assignForeignObjects(foreign, obj)}) {
+
+  return (HookedServiceEvent e) async {
+    var ref = e.service.app.service(servicePath);
+    var foreignName =
+        as?.isNotEmpty == true ? as : pluralize.plural(servicePath.toString());
+    if (ref == null) throw noService(servicePath);
+
+    _getLocalKey(obj) {
+      if (getLocalKey != null)
+        return getLocalKey(obj);
+      else if (obj is Map)
+        return obj[localKey ?? 'id'];
+      else if (obj is Extensible)
+        return obj.properties[localKey ?? 'id'];
+      else if (localKey == null || localKey == 'id')
+        return obj.id;
+      else
+        return reflect(obj).getField(new Symbol(localKey ?? 'id')).reflectee;
+    }
+
+    _assignForeignObjects(foreign, obj) {
+      if (assignForeignObjects != null)
+        return assignForeignObjects(foreign, obj);
+      else if (obj is Map)
+        obj[foreignName] = foreign;
+      else if (obj is Extensible)
+        obj.properties[foreignName] = foreign;
+      else
+        reflect(obj).setField(new Symbol(foreignName), foreign);
+    }
+
+    _normalize(obj) async {
+      if (obj != null) {
+        var id = await _getLocalKey(obj);
+        var indexed = await ref.index({
+          'query': {foreignKey ?? 'userId': id}
+        });
+
+        if (indexed == null || indexed is! List || indexed.isNotEmpty != true) {
+          await _assignForeignObjects([], obj);
+        } else {
+          await _assignForeignObjects(indexed, obj);
+        }
+      }
+    }
+
+    if (e.result is Iterable) {
+      await Future.wait(e.result.map(_normalize));
+    } else
+      await _normalize(e.result);
+  };
+}
diff --git a/packages/relations/lib/src/has_many_through.dart b/packages/relations/lib/src/has_many_through.dart
new file mode 100644
index 00000000..9539519e
--- /dev/null
+++ b/packages/relations/lib/src/has_many_through.dart
@@ -0,0 +1,100 @@
+import 'dart:async';
+import 'dart:mirrors';
+import 'package:angel_framework/angel_framework.dart';
+import 'plural.dart' as pluralize;
+import 'no_service.dart';
+
+HookedServiceEventListener hasManyThrough(String servicePath, String pivotPath,
+    {String as,
+    String localKey,
+    String pivotKey,
+    String foreignKey,
+    getLocalKey(obj),
+    getPivotKey(obj),
+    getForeignKey(obj),
+    assignForeignObjects(foreign, obj)}) {
+  var foreignName =
+      as?.isNotEmpty == true ? as : pluralize.plural(servicePath.toString());
+
+  return (HookedServiceEvent e) async {
+    var pivotService = e.getService(pivotPath);
+    var foreignService = e.getService(servicePath);
+
+    if (pivotService == null)
+      throw noService(pivotPath);
+    else if (foreignService == null) throw noService(servicePath);
+
+    _assignForeignObjects(foreign, obj) {
+      if (assignForeignObjects != null)
+        return assignForeignObjects(foreign, obj);
+      else if (obj is Map)
+        obj[foreignName] = foreign;
+      else if (obj is Extensible)
+        obj.properties[foreignName] = foreign;
+      else
+        reflect(obj).setField(new Symbol(foreignName), foreign);
+    }
+
+    _getLocalKey(obj) {
+      if (getLocalKey != null)
+        return getLocalKey(obj);
+      else if (obj is Map)
+        return obj[localKey ?? 'id'];
+      else if (obj is Extensible)
+        return obj.properties[localKey ?? 'id'];
+      else if (localKey == null || localKey == 'id')
+        return obj.id;
+      else
+        return reflect(obj).getField(new Symbol(localKey ?? 'id')).reflectee;
+    }
+
+    _getPivotKey(obj) {
+      if (getPivotKey != null)
+        return getPivotKey(obj);
+      else if (obj is Map)
+        return obj[pivotKey ?? 'id'];
+      else if (obj is Extensible)
+        return obj.properties[pivotKey ?? 'id'];
+      else if (pivotKey == null || pivotKey == 'id')
+        return obj.id;
+      else
+        return reflect(obj).getField(new Symbol(pivotKey ?? 'id')).reflectee;
+    }
+
+    _normalize(obj) async {
+      // First, resolve pivot
+      var id = await _getLocalKey(obj);
+      var indexed = await pivotService.index({
+        'query': {pivotKey ?? 'userId': id}
+      });
+
+      if (indexed == null || indexed is! List || indexed.isNotEmpty != true) {
+        await _assignForeignObjects([], obj);
+      } else {
+        // Now, resolve from foreign service
+        var mapped = await Future.wait(indexed.map((pivot) async {
+          var id = await _getPivotKey(obj);
+          var indexed = await foreignService.index({
+            'query': {foreignKey ?? 'postId': id}
+          });
+
+          if (indexed == null ||
+              indexed is! List ||
+              indexed.isNotEmpty != true) {
+            await _assignForeignObjects([], pivot);
+          } else {
+            await _assignForeignObjects(indexed, pivot);
+          }
+
+          return pivot;
+        }));
+        await _assignForeignObjects(mapped, obj);
+      }
+    }
+
+    if (e.result is Iterable) {
+      await Future.wait(e.result.map(_normalize));
+    } else
+      await _normalize(e.result);
+  };
+}
diff --git a/packages/relations/lib/src/has_one.dart b/packages/relations/lib/src/has_one.dart
new file mode 100644
index 00000000..8578081b
--- /dev/null
+++ b/packages/relations/lib/src/has_one.dart
@@ -0,0 +1,74 @@
+import 'dart:async';
+import 'dart:mirrors';
+import 'package:angel_framework/angel_framework.dart';
+import 'plural.dart' as pluralize;
+import 'no_service.dart';
+
+/// Represents a relationship in which the current [service] "owns"
+/// a single member of the service at [servicePath]. Use [as] to set the name
+/// on the target object.
+///
+/// Defaults:
+/// * [foreignKey]: `userId`
+/// * [localKey]: `id`
+HookedServiceEventListener hasOne(Pattern servicePath,
+    {String as,
+    String foreignKey,
+    String localKey,
+    getLocalKey(obj),
+    assignForeignObject(foreign, obj)}) {
+
+  return (HookedServiceEvent e) async {
+    var ref = e.service.app.service(servicePath);
+    var foreignName = as?.isNotEmpty == true
+        ? as
+        : pluralize.singular(servicePath.toString());
+    if (ref == null) throw noService(servicePath);
+
+    _getLocalKey(obj) {
+      if (getLocalKey != null)
+        return getLocalKey(obj);
+      else if (obj is Map)
+        return obj[localKey ?? 'id'];
+      else if (obj is Extensible)
+        return obj.properties[localKey ?? 'id'];
+      else if (localKey == null || localKey == 'id')
+        return obj.id;
+      else
+        return reflect(obj).getField(new Symbol(localKey ?? 'id')).reflectee;
+    }
+
+    _assignForeignObject(foreign, obj) {
+      if (assignForeignObject != null)
+        return assignForeignObject(foreign, obj);
+      else if (obj is Map)
+        obj[foreignName] = foreign;
+      else if (obj is Extensible)
+        obj.properties[foreignName] = foreign;
+      else
+        reflect(obj).setField(new Symbol(foreignName), foreign);
+    }
+
+    _normalize(obj) async {
+      if (obj != null) {
+        var id = await _getLocalKey(obj);
+
+        var indexed = await ref.index({
+          'query': {foreignKey ?? 'userId': id}
+        });
+
+        if (indexed == null || indexed is! List || indexed.isNotEmpty != true) {
+          await _assignForeignObject(null, obj);
+        } else {
+          var child = indexed.first;
+          await _assignForeignObject(child, obj);
+        }
+      }
+    }
+
+    if (e.result is Iterable) {
+      await Future.wait(e.result.map(_normalize));
+    } else
+      await _normalize(e.result);
+  };
+}
diff --git a/packages/relations/lib/src/no_service.dart b/packages/relations/lib/src/no_service.dart
new file mode 100644
index 00000000..e9d78658
--- /dev/null
+++ b/packages/relations/lib/src/no_service.dart
@@ -0,0 +1,2 @@
+ArgumentError noService(Pattern path) =>
+    new ArgumentError("No service exists at path '$path'.");
\ No newline at end of file
diff --git a/packages/relations/lib/src/plural.dart b/packages/relations/lib/src/plural.dart
new file mode 100644
index 00000000..972d2fdd
--- /dev/null
+++ b/packages/relations/lib/src/plural.dart
@@ -0,0 +1,21 @@
+String singular(String path) {
+  var str = path.trim().split('/').where((str) => str.isNotEmpty).last;
+
+  if (str.endsWith('ies'))
+    return str.substring(0, str.length - 3) + 'y';
+  else if (str.endsWith('s'))
+    return str.substring(0, str.length - 1);
+  else
+    return str;
+}
+
+String plural(String path) {
+  var str = path.trim().split('/').where((str) => str.isNotEmpty).last;
+
+  if (str.endsWith('y'))
+    return str.substring(0, str.length - 1) + 'ies';
+  else if (str.endsWith('s'))
+    return str;
+  else
+    return str + 's';
+}
diff --git a/packages/relations/pubspec.yaml b/packages/relations/pubspec.yaml
new file mode 100644
index 00000000..d25318d2
--- /dev/null
+++ b/packages/relations/pubspec.yaml
@@ -0,0 +1,12 @@
+author: Tobe O <thosakwe@gmail.com>
+description: Database-agnostic relations between Angel services.
+homepage: "https://github.com/angel-dart/relations.git"
+name: angel_relations
+version: 1.0.1
+environment:
+  sdk: ">=1.19.0"
+dependencies: 
+  angel_framework: ^1.0.0-dev
+dev_dependencies:
+  angel_seeder: ^1.0.0
+  test: ^0.12.0
diff --git a/packages/relations/test/belongs_to_test.dart b/packages/relations/test/belongs_to_test.dart
new file mode 100644
index 00000000..d398e923
--- /dev/null
+++ b/packages/relations/test/belongs_to_test.dart
@@ -0,0 +1,56 @@
+import 'package:angel_framework/angel_framework.dart';
+import 'package:angel_relations/angel_relations.dart' as relations;
+import 'package:angel_seeder/angel_seeder.dart';
+import 'package:test/test.dart';
+import 'common.dart';
+
+main() {
+  Angel app;
+
+  setUp(() async {
+    app = new Angel()
+      ..use('/authors', new MapService())
+      ..use('/books', new MapService());
+
+    await app.configure(seed(
+        'authors',
+        new SeederConfiguration<Map>(
+            count: 10,
+            template: {'name': (Faker faker) => faker.person.name()},
+            callback: (Map author, seed) {
+              return seed(
+                  'books',
+                  new SeederConfiguration(delete: false, count: 10, template: {
+                    'authorId': author['id'],
+                    'title': (Faker faker) =>
+                        'I love to eat ${faker.food.dish()}'
+                  }));
+            })));
+
+    app.service('books').afterAll(relations.belongsTo('authors'));
+  });
+
+  test('index', () async {
+    var books = await app.service('books').index();
+    print(books);
+
+    expect(books, allOf(isList, isNotEmpty));
+
+    for (Map book in books) {
+      expect(book.keys, contains('author'));
+
+      Map author = book['author'];
+      expect(author['id'], equals(book['authorId']));
+    }
+  });
+
+  test('create', () async {
+    var warAndPeace = await app
+        .service('books')
+        .create(new Book(title: 'War and Peace').toJson());
+
+    print(warAndPeace);
+    expect(warAndPeace.keys, contains('author'));
+    expect(warAndPeace['author'], isNull);
+  });
+}
diff --git a/packages/relations/test/common.dart b/packages/relations/test/common.dart
new file mode 100644
index 00000000..f8adf3dd
--- /dev/null
+++ b/packages/relations/test/common.dart
@@ -0,0 +1,68 @@
+import 'package:angel_framework/angel_framework.dart';
+import 'package:json_god/json_god.dart' as god;
+
+@deprecated
+class CustomMapService extends Service {
+  final List<Map> _items = [];
+
+  Iterable<Map> tailor(Iterable<Map> items, Map params) {
+    if (params == null) return items;
+
+    var r = items;
+
+    if (params != null && params['query'] is Map) {
+      Map query = params['query'];
+
+      for (var key in query.keys) {
+        r = r.where((m) => m[key] == query[key]);
+      }
+    }
+
+    return r;
+  }
+
+  @override
+  index([params]) async => tailor(_items, params).toList();
+
+  @override
+  read(id, [Map params]) async {
+    return tailor(_items, params).firstWhere((m) => m['id'] == id,
+        orElse: () => throw new AngelHttpException.notFound());
+  }
+
+  @override
+  create(data, [params]) async {
+    Map d = data is Map ? data : god.serializeObject(data);
+    d['id'] = _items.length.toString();
+    _items.add(d);
+    return d;
+  }
+
+  @override
+  remove(id, [params]) async {
+    if (id == null) _items.clear();
+  }
+}
+
+class Author {
+  String id, name;
+
+  Author({this.id, this.name});
+
+  Map toJson() => {'id': id, 'name': name};
+}
+
+class Book {
+  String authorId, title;
+
+  Book({this.authorId, this.title});
+
+  Map toJson() => {'authorId': authorId, 'title': title};
+}
+
+class Chapter {
+  String bookId, title;
+  int pageCount;
+
+  Chapter({this.bookId, this.title, this.pageCount});
+}
diff --git a/packages/relations/test/has_many_test.dart b/packages/relations/test/has_many_test.dart
new file mode 100644
index 00000000..e27b19e4
--- /dev/null
+++ b/packages/relations/test/has_many_test.dart
@@ -0,0 +1,61 @@
+import 'package:angel_framework/angel_framework.dart';
+import 'package:angel_relations/angel_relations.dart' as relations;
+import 'package:angel_seeder/angel_seeder.dart';
+import 'package:test/test.dart';
+import 'common.dart';
+
+main() {
+  Angel app;
+
+  setUp(() async {
+    app = new Angel()
+      ..use('/authors', new MapService())
+      ..use('/books', new MapService());
+
+    await app.configure(seed(
+        'authors',
+        new SeederConfiguration<Map>(
+            count: 10,
+            template: {'name': (Faker faker) => faker.person.name()},
+            callback: (Map author, seed) {
+              return seed(
+                  'books',
+                  new SeederConfiguration(delete: false, count: 10, template: {
+                    'authorId': author['id'],
+                    'title': (Faker faker) =>
+                        'I love to eat ${faker.food.dish()}'
+                  }));
+            })));
+
+    app
+        .service('authors')
+        .afterAll(relations.hasMany('books', foreignKey: 'authorId'));
+  });
+
+  test('index', () async {
+    var authors = await app.service('authors').index();
+    print(authors);
+
+    expect(authors, allOf(isList, isNotEmpty));
+
+    for (Map author in authors) {
+      expect(author.keys, contains('books'));
+
+      List<Map> books = author['books'];
+
+      for (var book in books) {
+        expect(book['authorId'], equals(author['id']));
+      }
+    }
+  });
+
+  test('create', () async {
+    var tolstoy = await app
+        .service('authors')
+        .create(new Author(name: 'Leo Tolstoy').toJson());
+
+    print(tolstoy);
+    expect(tolstoy.keys, contains('books'));
+    expect(tolstoy['books'], allOf(isList, isEmpty));
+  });
+}
diff --git a/packages/relations/test/has_one_test.dart b/packages/relations/test/has_one_test.dart
new file mode 100644
index 00000000..7169f545
--- /dev/null
+++ b/packages/relations/test/has_one_test.dart
@@ -0,0 +1,59 @@
+import 'package:angel_framework/angel_framework.dart';
+import 'package:angel_relations/angel_relations.dart' as relations;
+import 'package:angel_seeder/angel_seeder.dart';
+import 'package:test/test.dart';
+import 'common.dart';
+
+main() {
+  Angel app;
+
+  setUp(() async {
+    app = new Angel()
+      ..use('/authors', new MapService())
+      ..use('/books', new MapService());
+
+    await app.configure(seed(
+        'authors',
+        new SeederConfiguration<Map>(
+            count: 10,
+            template: {'name': (Faker faker) => faker.person.name()},
+            callback: (Map author, seed) {
+              return seed(
+                  'books',
+                  new SeederConfiguration(delete: false, count: 10, template: {
+                    'authorId': author['id'],
+                    'title': (Faker faker) =>
+                        'I love to eat ${faker.food.dish()}'
+                  }));
+            })));
+
+    app.service('authors').afterAll(
+        relations.hasOne('books', as: 'book', foreignKey: 'authorId'));
+  });
+
+  test('index', () async {
+    var authors = await app.service('authors').index();
+    print(authors);
+
+    expect(authors, allOf(isList, isNotEmpty));
+
+    for (Map author in authors) {
+      expect(author.keys, contains('book'));
+
+      Map book = author['book'];
+      print('Author: $author');
+      print('Book: $book');
+      expect(book['authorId'], equals(author['id']));
+    }
+  });
+
+  test('create', () async {
+    var tolstoy = await app
+        .service('authors')
+        .create(new Author(name: 'Leo Tolstoy').toJson());
+
+    print(tolstoy);
+    expect(tolstoy.keys, contains('book'));
+    expect(tolstoy['book'], isNull);
+  });
+}