addExtensionSql("ALTER TABLE `{?_MYSQL_PREFIX?}_config` ADD `refback_enabled` ENUM('Y','N') NOT NULL DEFAULT 'Y'");
addExtensionSql("ALTER TABLE `{?_MYSQL_PREFIX?}_config` ADD `refback_min_perc` TINYINT(3) NOT NULL DEFAULT 0");
addExtensionSql("ALTER TABLE `{?_MYSQL_PREFIX?}_config` ADD `refback_max_perc` TINYINT(3) NOT NULL DEFAULT 100");
addExtensionSql("ALTER TABLE `{?_MYSQL_PREFIX?}_config` ADD `refback_enabled` ENUM('Y','N') NOT NULL DEFAULT 'Y'");
addExtensionSql("ALTER TABLE `{?_MYSQL_PREFIX?}_config` ADD `refback_min_perc` TINYINT(3) NOT NULL DEFAULT 0");
addExtensionSql("ALTER TABLE `{?_MYSQL_PREFIX?}_config` ADD `refback_max_perc` TINYINT(3) NOT NULL DEFAULT 100");