diff --git a/app/DoctrineMigrations/Version20190227233244.php b/app/DoctrineMigrations/Version20190227233244.php
new file mode 100644
index 0000000..f253901
--- /dev/null
+++ b/app/DoctrineMigrations/Version20190227233244.php
@@ -0,0 +1,28 @@
+<?php declare(strict_types=1);
+
+namespace Application\Migrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+/**
+ * Auto-generated Migration: Please modify to your needs!
+ */
+final class Version20190227233244 extends AbstractMigration
+{
+    public function up(Schema $schema) : void
+    {
+        // this up() migration is auto-generated, please modify it to your needs
+        $this->abortIf($this->connection->getDatabasePlatform()->getName() !== 'postgresql', 'Migration can only be executed safely on \'postgresql\'.');
+
+        $this->addSql('CREATE UNIQUE INDEX unique_post_id_comment_number ON posts.comments (post_id, number)');
+    }
+
+    public function down(Schema $schema) : void
+    {
+        // this down() migration is auto-generated, please modify it to your needs
+        $this->abortIf($this->connection->getDatabasePlatform()->getName() !== 'postgresql', 'Migration can only be executed safely on \'postgresql\'.');
+
+        $this->addSql('DROP INDEX posts.unique_post_id_comment_number');
+    }
+}
diff --git a/src/Skobkin/Bundle/PointToolsBundle/Entity/Blogs/Comment.php b/src/Skobkin/Bundle/PointToolsBundle/Entity/Blogs/Comment.php
index 6c114f2..2d1937a 100644
--- a/src/Skobkin/Bundle/PointToolsBundle/Entity/Blogs/Comment.php
+++ b/src/Skobkin/Bundle/PointToolsBundle/Entity/Blogs/Comment.php
@@ -9,6 +9,8 @@ use Skobkin\Bundle\PointToolsBundle\Entity\User;
 /**
  * @ORM\Table(name="comments", schema="posts", indexes={
  *      @ORM\Index(name="idx_comment_created_at", columns={"created_at"})
+ * }, uniqueConstraints={
+ *      @ORM\UniqueConstraint(name="unique_post_id_comment_number", columns={"post_id", "number"})
  * })
  * @ORM\Entity(repositoryClass="Skobkin\Bundle\PointToolsBundle\Repository\Blogs\CommentRepository")
  */