diff --git a/install/dbscheme.txt b/install/dbscheme.txt
index ccd54e9c3..3ee5b8ea6 100644
--- a/install/dbscheme.txt
+++ b/install/dbscheme.txt
@@ -125,7 +125,6 @@ pk         group_id                       user_group
 pk         user_id                        user_group     
 pk         id                             users          
 pk         id                             waiting        
-index      categories_i1                  categories           id
 index      categories_i2                  categories           id_uppercat
 index      image_category_i1              image_category       image_id
 index      image_category_i2              image_category       category_id
diff --git a/install/phpwebgallery_structure.sql b/install/phpwebgallery_structure.sql
index c516f72d0..ba3102af0 100644
--- a/install/phpwebgallery_structure.sql
+++ b/install/phpwebgallery_structure.sql
@@ -25,7 +25,6 @@ CREATE TABLE phpwebgallery_categories (
   representative_picture_id mediumint(8) unsigned default NULL,
   uppercats varchar(255) NOT NULL default '',
   PRIMARY KEY  (id),
-  KEY categories_i1 (id),
   KEY categories_i2 (id_uppercat)
 ) TYPE=MyISAM;