diff --git a/database/entities/Database/Entities/BbAttachments.php b/database/entities/Database/Entities/BbAttachments.php
index dc947b64..3e156bb5 100644
--- a/database/entities/Database/Entities/BbAttachments.php
+++ b/database/entities/Database/Entities/BbAttachments.php
@@ -15,23 +15,22 @@ class BbAttachments
     /**
      * @var integer
      */
-    private $postId = '0';
+    private $postId;
 
     /**
      * @var integer
      */
-    private $userId1 = '0';
-
+    private $privmsgsId = 0;
 
     /**
      * @var integer
      */
-    private $privmsgsId = '0';
+    private $userId1 = 0;
 
     /**
      * @var integer
      */
-    private $userId2 = '0';
+    private $userId2 = 0;
 
 
 }
diff --git a/database/mappings/Database.Entities.BbAttachments.dcm.yml b/database/mappings/Database.Entities.BbAttachments.dcm.yml
index 5bab886f..1b131e2d 100644
--- a/database/mappings/Database.Entities.BbAttachments.dcm.yml
+++ b/database/mappings/Database.Entities.BbAttachments.dcm.yml
@@ -33,20 +33,20 @@ Database\Entities\BbAttachments:
             nullable: false
             options:
                 unsigned: true
-                default: '0'
+                default: 0
             column: privmsgs_id
         userId1:
             type: integer
             nullable: false
             options:
                 unsigned: false
-                default: '0'
+                default: 0
             column: user_id_1
         userId2:
             type: integer
             nullable: false
             options:
                 unsigned: false
-                default: '0'
+                default: 0
             column: user_id_2
     lifecycleCallbacks: {  }
diff --git a/database/mappings/Database.Entities.BbPrivmsgs.dcm.yml b/database/mappings/Database.Entities.BbPrivmsgs.dcm.yml
index 45ba4c6f..63810b6e 100644
--- a/database/mappings/Database.Entities.BbPrivmsgs.dcm.yml
+++ b/database/mappings/Database.Entities.BbPrivmsgs.dcm.yml
@@ -26,7 +26,7 @@ Database\Entities\BbPrivmsgs:
             type: boolean
             nullable: false
             options:
-                default: '0'
+                default: 0
             column: privmsgs_type
         privmsgsSubject:
             type: string
@@ -41,21 +41,21 @@ Database\Entities\BbPrivmsgs:
             nullable: false
             options:
                 unsigned: false
-                default: '0'
+                default: 0
             column: privmsgs_from_userid
         privmsgsToUserid:
             type: integer
             nullable: false
             options:
                 unsigned: false
-                default: '0'
+                default: 0
             column: privmsgs_to_userid
         privmsgsDate:
             type: integer
             nullable: false
             options:
                 unsigned: false
-                default: '0'
+                default: 0
             column: privmsgs_date
         privmsgsIp:
             type: string
diff --git a/database/migrations/Version20170601000000.php b/database/migrations/Version20170601000000.php
index 036a8f77..9f6fc5b5 100644
--- a/database/migrations/Version20170601000000.php
+++ b/database/migrations/Version20170601000000.php
@@ -354,12 +354,18 @@ public function up(Schema $schema)
          * Modify tables
          ******************/
 
-        // bb_attachments
+        /**
+         * bb_attachments
+         * @see https://github.com/hurtom/toloka/issues/27
+         */
         $this->addSql('DROP INDEX attach_id_post_id ON bb_attachments');
         $this->addSql('DROP INDEX post_id ON bb_attachments');
         $this->addSql('ALTER TABLE bb_attachments
             CHANGE attach_id attach_id INT UNSIGNED NOT NULL,
             CHANGE post_id post_id INT UNSIGNED NOT NULL,
+            CHANGE privmsgs_id privmsgs_id INT UNSIGNED DEFAULT 0 NOT NULL,
+            CHANGE user_id_1 user_id_1 INT DEFAULT 0 NOT NULL,
+            CHANGE user_id_2 user_id_2 INT DEFAULT 0 NOT NULL,
             ADD PRIMARY KEY (attach_id, post_id),
             ENGINE = InnoDB');
 
@@ -786,6 +792,7 @@ public function up(Schema $schema)
             DROP privmsgs_enable_smilies,
             DROP privmsgs_attach_sig,
             DROP privmsgs_attachment,
+            CHANGE privmsgs_id privmsgs_id INT UNSIGNED NOT NULL,
             CHANGE privmsgs_subject privmsgs_subject VARCHAR(255) DEFAULT \'0\' NOT NULL,
             CHANGE privmsgs_ip privmsgs_ip VARCHAR(42) DEFAULT \'0\' NOT NULL COLLATE utf8_bin,
             ENGINE = InnoDB');