diff --git a/gemeinsamforschen/src/scripts/dbschema/fltrail.sql b/gemeinsamforschen/src/scripts/dbschema/fltrail.sql
index 372f245e179a1d4da88926141a072e27e021cd82..11c65982147c30144dbac322771ebf79d051eed9 100644
--- a/gemeinsamforschen/src/scripts/dbschema/fltrail.sql
+++ b/gemeinsamforschen/src/scripts/dbschema/fltrail.sql
@@ -32,10 +32,11 @@ CREATE TABLE if not exists `tags` (
 CREATE TABLE if not exists `users` (
   `name`                varchar(400) NOT NULL,
   `password`            varchar(200) NOT NULL,
-  `email`               varchar(400) NOT NULL,
+  `email`               varchar(255) NOT NULL,
   `token`               varchar(800) NOT NULL,
   `rocketChatId`        varchar(400) NOT NULL,
-  `rocketChatAuthToken` varchar(800) NOT NULL
+  `rocketChatAuthToken` varchar(800) NOT NULL,
+  UNIQUE (email)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
 
 CREATE TABLE if not exists projectuser