Add unique constraints for ssh login user and login user mapping tables

backend/src/db/migrations/20250405185753_ssh-mgmt-v2.ts

@@ -29,6 +29,7 @@ export async function up(knex: Knex): Promise<void> {
       t.uuid("sshHostId").notNullable();
       t.foreign("sshHostId").references("id").inTable(TableName.SshHost).onDelete("CASCADE");
       t.string("loginUser").notNullable(); // e.g. ubuntu, root, ec2-user, ...
+      t.unique(["sshHostId", "loginUser"]);
     });
     await createOnUpdateTrigger(knex, TableName.SshHostLoginUser);
   }
@@ -41,6 +42,7 @@ export async function up(knex: Knex): Promise<void> {
       t.foreign("sshHostLoginUserId").references("id").inTable(TableName.SshHostLoginUser).onDelete("CASCADE");
       t.uuid("userId").nullable();
       t.foreign("userId").references("id").inTable(TableName.Users).onDelete("CASCADE");
+      t.unique(["sshHostLoginUserId", "userId"]);
     });
     await createOnUpdateTrigger(knex, TableName.SshHostLoginUserMapping);
   }

backend/src/ee/services/ssh-host/ssh-host-service.ts

@@ -188,20 +188,6 @@ export const sshHostServiceFactory = ({
     });
 
     const newSshHost = await sshHostDAL.transaction(async (tx) => {
-      const existingHost = await sshHostDAL.findOne(
-        {
-          projectId,
-          hostname
-        },
-        tx
-      );
-
-      if (existingHost) {
-        throw new BadRequestError({
-          message: `SSH host with hostname ${hostname} already exists`
-        });
-      }
-
       const host = await sshHostDAL.create(
         {
           projectId,