diff --git a/crates/oxidetalis/src/database/out_chat_requests.rs b/crates/oxidetalis/src/database/out_chat_requests.rs
index df8840c..f0cb280 100644
--- a/crates/oxidetalis/src/database/out_chat_requests.rs
+++ b/crates/oxidetalis/src/database/out_chat_requests.rs
@@ -69,21 +69,23 @@ impl OutChatRequestsExt for DatabaseConnection {
         requester: &UserModel,
         recipient: &PublicKey,
     ) -> ServerResult<()> {
-        if self
-            .have_chat_request_to(requester, recipient)
-            .await?
-            .is_some()
-        {
-            return Err(WsError::AlreadySendChatRequest.into());
-        }
-        OutChatRequestsActiveModel {
+        if let Err(err) = (OutChatRequestsActiveModel {
             sender_id: Set(requester.id),
             recipient: Set(recipient.to_string()),
             out_on: Set(Utc::now()),
             ..Default::default()
         }
         .save(self)
-        .await?;
+        .await)
+        {
+            match err.sql_err() {
+                Some(SqlErr::UniqueConstraintViolation(_)) => {
+                    return Err(WsError::AlreadySendChatRequest.into());
+                }
+                _ => return Err(err.into()),
+            }
+        }
+
         Ok(())
     }
 
diff --git a/crates/oxidetalis_migrations/src/create_outgoing_chat_requests_table.rs b/crates/oxidetalis_migrations/src/create_outgoing_chat_requests_table.rs
index 6880157..d033bc3 100644
--- a/crates/oxidetalis_migrations/src/create_outgoing_chat_requests_table.rs
+++ b/crates/oxidetalis_migrations/src/create_outgoing_chat_requests_table.rs
@@ -29,6 +29,19 @@ pub struct Migration;
 #[async_trait::async_trait]
 impl MigrationTrait for Migration {
     async fn up(&self, manager: &SchemaManager) -> Result<(), DbErr> {
+        manager
+            .create_index(
+                Index::create()
+                    .if_not_exists()
+                    .name("sep_request")
+                    .table(OutChatRequests::Table)
+                    .col(OutChatRequests::SenderId)
+                    .col(OutChatRequests::Recipient)
+                    .unique()
+                    .to_owned(),
+            )
+            .await?;
+
         manager
             .create_table(
                 Table::create()