diff --git a/db/builder_db.ml b/db/builder_db.ml
index 494e921..54c958e 100644
--- a/db/builder_db.ml
+++ b/db/builder_db.ml
@@ -157,13 +157,15 @@ module Job_tag = struct
   let add =
     Caqti_request.exec
       Caqti_type.(tup3 id string id)
-      {| INSERT INTO job_tag (tag, value, job)
-         VALUES (?1, ?2, ?3)
-         ON CONFLICT(x) DO UPDATE SET value = ?2 WHERE tag = ?1 AND job = ?3
-      |}
+      "INSERT INTO job_tag (tag, value, job) VALUES (?1, ?2, ?3)"
+
+  let update =
+    Caqti_request.exec
+      Caqti_type.(tup3 id string id)
+      "UPDATE job_tag SET value = ?2 WHERE tag = ?1 AND job = ?3"
 
   let get_value =
-    Caqti_request.find
+    Caqti_request.find_opt
       Caqti_type.(tup2 id id)
       Caqti_type.string
       "SELECT value FROM job_tag WHERE tag = ? AND job = ?"
diff --git a/db/builder_db.mli b/db/builder_db.mli
index 0357343..70973e0 100644
--- a/db/builder_db.mli
+++ b/db/builder_db.mli
@@ -85,8 +85,10 @@ module Job_tag : sig
     (unit, unit, [< `Many | `One | `Zero > `Zero ]) Caqti_request.t
   val add :
     (id * string * id, unit, [< `Many | `One | `Zero > `Zero ]) Caqti_request.t
+  val update :
+    (id * string * id, unit, [< `Many | `One | `Zero > `Zero ]) Caqti_request.t
   val get_value :
-    (id * id, string, [< `Many | `One | `Zero > `One ]) Caqti_request.t
+    (id * id, string, [< `Many | `One | `Zero > `Zero `One ]) Caqti_request.t
 end
 
 module Build_artifact : sig
diff --git a/lib/model.ml b/lib/model.ml
index 141c645..05ab72c 100644
--- a/lib/model.ml
+++ b/lib/model.ml
@@ -270,15 +270,20 @@ let add_build
                         main_binary = None; user_id; job_id } >>= fun () ->
     Db.find last_insert_rowid () >>= fun id ->
     let sec_syn = infer_section_and_synopsis raw_artifacts in
+    let add_or_update tag_id tag_value =
+      Db.find_opt Job_tag.get_value (tag_id, job_id) >>= function
+      | None -> Db.exec Job_tag.add (tag_id, tag_value, job_id)
+      | Some _ -> Db.exec Job_tag.update (tag_id, tag_value, job_id)
+    in
     (match fst sec_syn with
     | None -> Lwt_result.return ()
-    | Some section_v -> Db.exec Job_tag.add (section_id, section_v, id)) >>= fun () ->
+    | Some section_v -> add_or_update section_id section_v) >>= fun () ->
     (match snd sec_syn with
     | None, _-> Lwt_result.return ()
-    | Some synopsis_v, _ -> Db.exec Job_tag.add (synopsis_id, synopsis_v, id)) >>= fun () ->
+    | Some synopsis_v, _ -> add_or_update synopsis_id synopsis_v) >>= fun () ->
     (match snd sec_syn with
     | _, None -> Lwt_result.return ()
-    | _, Some descr_v -> Db.exec Job_tag.add (descr_id, descr_v, id)) >>= fun () ->
+    | _, Some descr_v -> add_or_update descr_id descr_v) >>= fun () ->
     List.fold_left
       (fun r file ->
          r >>= fun () ->