diff --git a/application/migrations/sqlscripts/attributes.sql b/application/migrations/sqlscripts/attributes.sql
index 74a61100b..66641d298 100644
--- a/application/migrations/sqlscripts/attributes.sql
+++ b/application/migrations/sqlscripts/attributes.sql
@@ -13,7 +13,7 @@ CREATE TABLE IF NOT EXISTS `ospos_attribute_definitions` (
 
 CREATE TABLE IF NOT EXISTS `ospos_attribute_values` (
  `attribute_id` INT NOT NULL AUTO_INCREMENT,
- `attribute_value` VARCHAR(255) NULL,
+ `attribute_value` VARCHAR(255) UNIQUE NULL,
  `attribute_datetime` DATETIME NULL,
  PRIMARY KEY (`attribute_id`)
 ) ENGINE = InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_general_ci;
@@ -88,16 +88,16 @@ INSERT INTO ospos_attribute_links (definition_id, item_id) SELECT definition_id,
 INSERT INTO ospos_attribute_links (definition_id, item_id) SELECT definition_id, item_id FROM ospos_attribute_definitions, ospos_app_config, ospos_items
  WHERE ospos_app_config.`key` = 'custom10_name' AND ospos_app_config.`value` = ospos_attribute_definitions.definition_name AND custom10 IS NOT NULL AND custom10 != '';
 
-INSERT INTO ospos_attribute_values (attribute_value) SELECT DISTINCT custom1 FROM ospos_items WHERE custom1 <> '' AND '' <> (SELECT `value` FROM ospos_app_config WHERE `key` = 'custom1_name');
-INSERT INTO ospos_attribute_values (attribute_value) SELECT DISTINCT custom2 FROM ospos_items WHERE custom2 <> '' AND '' <> (SELECT `value` FROM ospos_app_config WHERE `key` = 'custom2_name');
-INSERT INTO ospos_attribute_values (attribute_value) SELECT DISTINCT custom3 FROM ospos_items WHERE custom3 <> '' AND '' <> (SELECT `value` FROM ospos_app_config WHERE `key` = 'custom3_name');
-INSERT INTO ospos_attribute_values (attribute_value) SELECT DISTINCT custom4 FROM ospos_items WHERE custom4 <> '' AND '' <> (SELECT `value` FROM ospos_app_config WHERE `key` = 'custom4_name');
-INSERT INTO ospos_attribute_values (attribute_value) SELECT DISTINCT custom5 FROM ospos_items WHERE custom5 <> '' AND '' <> (SELECT `value` FROM ospos_app_config WHERE `key` = 'custom5_name');
-INSERT INTO ospos_attribute_values (attribute_value) SELECT DISTINCT custom6 FROM ospos_items WHERE custom6 <> '' AND '' <> (SELECT `value` FROM ospos_app_config WHERE `key` = 'custom6_name');
-INSERT INTO ospos_attribute_values (attribute_value) SELECT DISTINCT custom7 FROM ospos_items WHERE custom7 <> '' AND '' <> (SELECT `value` FROM ospos_app_config WHERE `key` = 'custom7_name');
-INSERT INTO ospos_attribute_values (attribute_value) SELECT DISTINCT custom8 FROM ospos_items WHERE custom8 <> '' AND '' <> (SELECT `value` FROM ospos_app_config WHERE `key` = 'custom8_name');
-INSERT INTO ospos_attribute_values (attribute_value) SELECT DISTINCT custom9 FROM ospos_items WHERE custom9 <> '' AND '' <> (SELECT `value` FROM ospos_app_config WHERE `key` = 'custom9_name');
-INSERT INTO ospos_attribute_values (attribute_value) SELECT DISTINCT custom10 FROM ospos_items WHERE custom10 <> '' AND '' <> (SELECT `value` FROM ospos_app_config WHERE `key` = 'custom10_name');
+INSERT IGNORE INTO ospos_attribute_values (attribute_value) SELECT DISTINCT custom1 FROM ospos_items WHERE custom1 <> '' AND '' <> (SELECT `value` FROM ospos_app_config WHERE `key` = 'custom1_name');
+INSERT IGNORE INTO ospos_attribute_values (attribute_value) SELECT DISTINCT custom2 FROM ospos_items WHERE custom2 <> '' AND '' <> (SELECT `value` FROM ospos_app_config WHERE `key` = 'custom2_name');
+INSERT IGNORE INTO ospos_attribute_values (attribute_value) SELECT DISTINCT custom3 FROM ospos_items WHERE custom3 <> '' AND '' <> (SELECT `value` FROM ospos_app_config WHERE `key` = 'custom3_name');
+INSERT IGNORE INTO ospos_attribute_values (attribute_value) SELECT DISTINCT custom4 FROM ospos_items WHERE custom4 <> '' AND '' <> (SELECT `value` FROM ospos_app_config WHERE `key` = 'custom4_name');
+INSERT IGNORE INTO ospos_attribute_values (attribute_value) SELECT DISTINCT custom5 FROM ospos_items WHERE custom5 <> '' AND '' <> (SELECT `value` FROM ospos_app_config WHERE `key` = 'custom5_name');
+INSERT IGNORE INTO ospos_attribute_values (attribute_value) SELECT DISTINCT custom6 FROM ospos_items WHERE custom6 <> '' AND '' <> (SELECT `value` FROM ospos_app_config WHERE `key` = 'custom6_name');
+INSERT IGNORE INTO ospos_attribute_values (attribute_value) SELECT DISTINCT custom7 FROM ospos_items WHERE custom7 <> '' AND '' <> (SELECT `value` FROM ospos_app_config WHERE `key` = 'custom7_name');
+INSERT IGNORE INTO ospos_attribute_values (attribute_value) SELECT DISTINCT custom8 FROM ospos_items WHERE custom8 <> '' AND '' <> (SELECT `value` FROM ospos_app_config WHERE `key` = 'custom8_name');
+INSERT IGNORE INTO ospos_attribute_values (attribute_value) SELECT DISTINCT custom9 FROM ospos_items WHERE custom9 <> '' AND '' <> (SELECT `value` FROM ospos_app_config WHERE `key` = 'custom9_name');
+INSERT IGNORE INTO ospos_attribute_values (attribute_value) SELECT DISTINCT custom10 FROM ospos_items WHERE custom10 <> '' AND '' <> (SELECT `value` FROM ospos_app_config WHERE `key` = 'custom10_name');
 
 UPDATE ospos_attribute_links
  INNER JOIN ospos_items ON ospos_attribute_links.item_id = ospos_items.item_id