diff --git a/src/generator.js b/src/generator.js
index 7c4f480..b5dc8df 100644
--- a/src/generator.js
+++ b/src/generator.js
@@ -153,9 +153,18 @@ export const loadModels = configuration => {
             'key',
           );
 
-          Index(foreignKeyIndexName, [attributeName], { unique: false })(
-            Skeleton,
-          );
+          let unique = false;
+          // checking if there is a defined index for the foreign key
+          if (entity.indexes) {
+            const definedForeignKeyIndex = entity.indexes.filter(index =>
+              _.isEqual(index.attributes, [attributeName]),
+            );
+            if (definedForeignKeyIndex && definedForeignKeyIndex.length > 0) {
+              unique = definedForeignKeyIndex[0].type === INDEX_UNIQUE;
+            }
+          }
+
+          Index(foreignKeyIndexName, [attributeName], { unique })(Skeleton);
           foreignKeyIndices.push(foreignKeyIndexName);
         }
 
diff --git a/test/__snapshots__/integration.spec.js.snap b/test/__snapshots__/integration.spec.js.snap
index f6e74cc..e14c57a 100644
--- a/test/__snapshots__/integration.spec.js.snap
+++ b/test/__snapshots__/integration.spec.js.snap
@@ -2,11 +2,33 @@
 
 exports[`postgres should check the generated indexes: indexList 1`] = `
 Array [
-  "PK_865a0f2e22c140d261b1df80eb1",
-  "board_created_by_key",
-  "board_is_private_key",
-  "board_name_key",
-  "board_owner_key",
-  "board_updated_by_key",
+  Object {
+    "indexname": "PK_865a0f2e22c140d261b1df80eb1",
+    "unique": true,
+  },
+  Object {
+    "indexname": "board_created_by_key",
+    "unique": false,
+  },
+  Object {
+    "indexname": "board_is_private_key",
+    "unique": false,
+  },
+  Object {
+    "indexname": "board_name_key",
+    "unique": true,
+  },
+  Object {
+    "indexname": "board_owner_key",
+    "unique": false,
+  },
+  Object {
+    "indexname": "board_updated_by_key",
+    "unique": false,
+  },
+  Object {
+    "indexname": "board_vip_key",
+    "unique": true,
+  },
 ]
 `;
diff --git a/test/data/boards.csv b/test/data/boards.csv
index b2f4b2e..2809df8 100644
--- a/test/data/boards.csv
+++ b/test/data/boards.csv
@@ -1,50 +1,50 @@
-Reiciendis quaerat,37,0
-Et eum,46,1
-Occaecati adipisci vel,79,1
-Delectus qui maxime,42,0
-Cumque impedit est,55,1
-Ut et,42,1
-Vel ullam,72,1
-Illo sit quia,59,1
-Veritatis nihil cum,52,1
-Sit aut,71,1
-Aut incidunt consequatur,81,0
-Tenetur porro,23,0
-Suscipit aut cum,84,0
-Id cum,26,0
-Sunt nobis,60,0
-Est adipisci inventore,73,0
-Est et,24,0
-In ipsum est,75,0
-Rerum ad,48,0
-Sunt quo,10,0
-Quia sapiente,62,0
-Excepturi amet animi,88,1
-Aut molestiae,12,0
-Non iusto unde,30,1
-Libero similique vitae,38,0
-Blanditiis cumque nisi,29,0
-Mollitia qui,14,0
-Deleniti esse itaque,13,0
-Ut provident assumenda,73,0
-Fuga accusantium voluptatem,6,0
-Culpa facilis,20,0
-Aliquam voluptates,78,1
-Suscipit quas,47,1
-Voluptas dolor,71,0
-Voluptatum necessitatibus molestias,17,0
-Consectetur blanditiis consequatur,40,0
-Voluptate tempora veritatis,42,0
-Nesciunt nihil enim,37,0
-Expedita qui,61,1
-Dignissimos est perferendis,65,0
-Enim dolore,27,0
-Quo ut rerum,37,1
-Sapiente laborum non,61,1
-Qui rem ut,9,0
-Sed necessitatibus facilis,85,1
-Et architecto,63,1
-Accusamus sequi,23,0
-Nobis totam,41,1
-Odit qui,26,1
-Sed assumenda repellendus,84,1
+Reiciendis quaerat,37,0,103
+Et eum,46,1,62
+Occaecati adipisci vel,79,1,50
+Delectus qui maxime,42,0,10
+Cumque impedit est,55,1,4
+Ut et,42,1,102
+Vel ullam,72,1,9
+Illo sit quia,59,1,21
+Veritatis nihil cum,52,1,61
+Sit aut,71,1,73
+Aut incidunt consequatur,81,0,12
+Tenetur porro,23,0,83
+Suscipit aut cum,84,0,89
+Id cum,26,0,26
+Sunt nobis,60,0,72
+Est adipisci inventore,73,0,14
+Est et,24,0,55
+In ipsum est,75,0,57
+Rerum ad,48,0,71
+Sunt quo,10,0,59
+Quia sapiente,62,0,93
+Excepturi amet animi,88,1,22
+Aut molestiae,12,0,51
+Non iusto unde,30,1,85
+Libero similique vitae,38,0,91
+Blanditiis cumque nisi,29,0,65
+Mollitia qui,14,0,45
+Deleniti esse itaque,13,0,48
+Ut provident assumenda,73,0,42
+Fuga accusantium voluptatem,6,0,19
+Culpa facilis,20,0,15
+Aliquam voluptates,78,1,82
+Suscipit quas,47,1,96
+Voluptas dolor,71,0,69
+Voluptatum necessitatibus molestias,17,0,3
+Consectetur blanditiis consequatur,40,0,81
+Voluptate tempora veritatis,42,0,36
+Nesciunt nihil enim,37,0,52
+Expedita qui,61,1,41
+Dignissimos est perferendis,65,0,107
+Enim dolore,27,0,17
+Quo ut rerum,37,1,7
+Sapiente laborum non,61,1,70
+Qui rem ut,9,0,29
+Sed necessitatibus facilis,85,1,74
+Et architecto,63,1,109
+Accusamus sequi,23,0,32
+Nobis totam,41,1,35
+Odit qui,26,1,101
+Sed assumenda repellendus,84,1,16
diff --git a/test/integration.spec.js b/test/integration.spec.js
index cd8536a..8f410ae 100644
--- a/test/integration.spec.js
+++ b/test/integration.spec.js
@@ -26,13 +26,14 @@ describe('postgres', () => {
     const storageInstance = StorageTypePostgres.getStorageInstance();
     const manager = storageInstance.manager;
     const indexes = await manager.query(`
-      select indexname
+      select
+        indexname,
+        indexdef ILIKE '%UNIQUE%' AS unique
       from pg_indexes
       where tablename = 'board'
       order by indexname
     `);
 
-    const indexList = indexes.map(i => i.indexname);
-    expect(indexList).toMatchSnapshot('indexList');
+    expect(indexes).toMatchSnapshot('indexList');
   });
 });
diff --git a/test/loadData.js b/test/loadData.js
index 904bdca..b240e5b 100644
--- a/test/loadData.js
+++ b/test/loadData.js
@@ -27,10 +27,11 @@ export const loadData = async () => {
 
   const boards = readRows('boards');
 
-  await asyncForEach(boards, async ([name, userId, isPrivate]) => {
+  await asyncForEach(boards, async ([name, userId, isPrivate, vip]) => {
     const payload = {
       name,
       isPrivate: isPrivate === '1',
+      vip,
     };
 
     await mutate(Board, 'build', payload, null, asUser(userId));
diff --git a/test/models/Board.js b/test/models/Board.js
index de58253..9c65261 100644
--- a/test/models/Board.js
+++ b/test/models/Board.js
@@ -44,6 +44,10 @@ export const Board = new Entity({
       type: INDEX_GENERIC,
       attributes: ['owner'],
     }),
+    new Index({
+      type: INDEX_UNIQUE,
+      attributes: ['vip'],
+    }),
   ],
 
   mutations: ({ createMutation }) => [
@@ -52,13 +56,13 @@ export const Board = new Entity({
       name: 'build',
       description: 'build a new board',
       type: MUTATION_TYPE_CREATE,
-      attributes: ['name', 'isPrivate'],
+      attributes: ['name', 'isPrivate', 'vip'],
     }),
     new Mutation({
       name: 'update',
       description: 'update a board',
       type: MUTATION_TYPE_UPDATE,
-      attributes: ['name', 'isPrivate'],
+      attributes: ['name', 'isPrivate', 'vip'],
     }),
   ],
 
@@ -86,6 +90,12 @@ export const Board = new Entity({
       },
     },
 
+    vip: {
+      type: Profile,
+      description: 'VIP guest of the board',
+      required: true,
+    },
+
     isPrivate: {
       type: DataTypeBoolean,
       description: 'It is a private board',
diff --git a/test/mutation.spec.js b/test/mutation.spec.js
index 564e3c6..8fd4852 100644
--- a/test/mutation.spec.js
+++ b/test/mutation.spec.js
@@ -114,6 +114,7 @@ describe('mutation', () => {
     const payload = {
       name: 'New Board',
       isPrivate: false,
+      vip: 1,
     };
 
     await mutate(Board, 'build', payload, null, asUser(99));
diff --git a/test/testUtils.js b/test/testUtils.js
index 793ce43..c159aa4 100644
--- a/test/testUtils.js
+++ b/test/testUtils.js
@@ -35,6 +35,10 @@ export const removeDynamicData = (entity, payload) => {
     delete ret.registeredAt;
   }
 
+  if (entity.name === 'Board') {
+    delete ret.vip;
+  }
+
   return ret;
 };