diff --git a/app/models/ues.py b/app/models/ues.py
index 1daf1273..c51d83ae 100644
--- a/app/models/ues.py
+++ b/app/models/ues.py
@@ -5,6 +5,7 @@ from flask import g
 import pandas as pd
 
 from app import db, log
+from app import models
 from app.models import APO_CODE_STR_LEN
 from app.models import SHORT_STR_LEN
 from app.models.but_refcomp import ApcNiveau, ApcParcours
@@ -12,7 +13,7 @@ from app.models.modules import Module
 from app.scodoc import sco_utils as scu
 
 
-class UniteEns(db.Model):
+class UniteEns(models.ScoDocModel):
     """Unité d'Enseignement (UE)"""
 
     __tablename__ = "notes_ue"
@@ -81,7 +82,7 @@ class UniteEns(db.Model):
             'EXTERNE' if self.is_external else ''})>"""
 
     def clone(self):
-        """Create a new copy of this ue.
+        """Create a new copy of this ue, add to session.
         Ne copie pas le code, ni le code Apogée, ni les liens au réf. de comp.
         (parcours et niveau).
         """
@@ -100,8 +101,26 @@ class UniteEns(db.Model):
             coef_rcue=self.coef_rcue,
             color=self.color,
         )
+        db.session.add(ue)
         return ue
 
+    @classmethod
+    def convert_dict_fields(cls, args: dict) -> dict:
+        """Convert fields from the given dict to model's attributes values. No side effect.
+
+        args: dict with args in application.
+        returns: dict to store in model's db.
+        """
+        args = args.copy()
+        if "type" in args:
+            args["type"] = int(args["type"] or 0)
+        if "is_external" in args:
+            args["is_external"] = scu.to_bool(args["is_external"])
+        if "ects" in args:
+            args["ects"] = float(args["ects"])
+
+        return args
+
     def to_dict(self, convert_objects=False, with_module_ue_coefs=True):
         """as a dict, with the same conversions as in ScoDoc7.
         If convert_objects, convert all attributes to native types
diff --git a/app/scodoc/notesdb.py b/app/scodoc/notesdb.py
index 3aba1848..57f03bd3 100644
--- a/app/scodoc/notesdb.py
+++ b/app/scodoc/notesdb.py
@@ -300,6 +300,7 @@ class EditableTable(object):
         output_formators={},
         input_formators={},
         aux_tables=[],
+        convert_empty_to_nulls=True,  # les arguments vides sont traduits en NULL
         convert_null_outputs_to_empty=True,
         html_quote=False,  # changed in 9.0.10
         fields_creators={},  # { field : [ sql_command_to_create_it ] }
@@ -321,6 +322,7 @@ class EditableTable(object):
         self.output_formators = output_formators
         self.input_formators = input_formators
         self.convert_null_outputs_to_empty = convert_null_outputs_to_empty
+        self.convert_empty_to_nulls = convert_empty_to_nulls
         self.html_quote = html_quote
         self.fields_creators = fields_creators
         self.filter_nulls = filter_nulls
@@ -351,6 +353,7 @@ class EditableTable(object):
             self.table_name,
             vals,
             commit=True,
+            convert_empty_to_nulls=self.convert_empty_to_nulls,
             return_id=(self.id_name is not None),
             ignore_conflicts=self.insert_ignore_conflicts,
         )
@@ -444,7 +447,7 @@ def dictfilter(d, fields, filter_nulls=True):
     """returns a copy of d with only keys listed in "fields" and non null values"""
     r = {}
     for f in fields:
-        if f in d and (d[f] != None or not filter_nulls):
+        if f in d and (d[f] is not None or not filter_nulls):
             try:
                 val = d[f].strip()
             except:
diff --git a/app/scodoc/sco_edit_ue.py b/app/scodoc/sco_edit_ue.py
index 06975ba3..f33eeacd 100644
--- a/app/scodoc/sco_edit_ue.py
+++ b/app/scodoc/sco_edit_ue.py
@@ -89,6 +89,7 @@ _ueEditor = ndb.EditableTable(
         "color",
         "niveau_competence_id",
     ),
+    convert_empty_to_nulls=False,  # necessaire pour ue_code == ""
     sortkey="numero",
     input_formators={
         "type": ndb.int_null_is_zero,
@@ -110,7 +111,7 @@ def ue_list(*args, **kw):
     return _ueEditor.list(cnx, *args, **kw)
 
 
-def do_ue_create(args):
+def do_ue_create(args, allow_empty_ue_code=False):
     "create an ue"
     cnx = ndb.GetDBConnexion()
     # check duplicates
@@ -120,18 +121,18 @@ def do_ue_create(args):
             f"""Acronyme d'UE "{args['acronyme']}" déjà utilisé !
                 (chaque UE doit avoir un acronyme unique dans la formation)"""
         )
-    if (
-        (not "ue_code" in args)
-        or (args["ue_code"] is None)
-        or (not args["ue_code"].strip())
-    ):
-        # évite les conflits de code
-        while True:
-            cursor = db.session.execute(sa.text("select notes_newid_ucod();"))
-            code = cursor.fetchone()[0]
-            if UniteEns.query.filter_by(ue_code=code).count() == 0:
-                break
-        args["ue_code"] = code
+    if "ue_code" not in args or args["ue_code"] is None or not args["ue_code"].strip():
+        if allow_empty_ue_code:
+            args["ue_code"] = ""
+        else:
+            # évite les conflits: génère nouveau ue_code
+            while True:
+                cursor = db.session.execute(sa.text("select notes_newid_ucod();"))
+                code = cursor.fetchone()[0]
+                if UniteEns.query.filter_by(ue_code=code).count() == 0:
+                    break
+            args["ue_code"] = code
+
     # create
     ue_id = _ueEditor.create(cnx, args)
     log(f"do_ue_create: created {ue_id} with {args}")
diff --git a/app/scodoc/sco_formation_versions.py b/app/scodoc/sco_formation_versions.py
index 8c74ad25..8fbf3931 100644
--- a/app/scodoc/sco_formation_versions.py
+++ b/app/scodoc/sco_formation_versions.py
@@ -168,16 +168,14 @@ def formsemestre_associate_new_version(
                     formation_id=new_formation_id,
                 )
             )
-        else:
-            return flask.redirect(
-                url_for(
-                    "notes.formsemestre_status",
-                    scodoc_dept=g.scodoc_dept,
-                    formsemestre_id=formsemestre_id,
-                )
+        return flask.redirect(
+            url_for(
+                "notes.formsemestre_status",
+                scodoc_dept=g.scodoc_dept,
+                formsemestre_id=formsemestre_id,
             )
-    else:
-        raise ScoValueError("Méthode invalide")
+        )
+    raise ScoValueError("Méthode invalide")
 
 
 def do_formsemestres_associate_new_version(
diff --git a/app/scodoc/sco_formations.py b/app/scodoc/sco_formations.py
index 1939d7f1..b0090819 100644
--- a/app/scodoc/sco_formations.py
+++ b/app/scodoc/sco_formations.py
@@ -117,6 +117,7 @@ def formation_export_dict(
     ues = ues.all()
     ues.sort(key=lambda u: (u.semestre_idx or 0, u.numero or 0, u.acronyme))
     f_dict["ue"] = []
+    ue: UniteEns
     for ue in ues:
         ue_dict = ue.to_dict()
         f_dict["ue"].append(ue_dict)
@@ -363,7 +364,9 @@ def formation_import_xml(doc: str, import_tags=True, use_local_refcomp=False):
                 ue_info[1]["niveau_competence_id"] = _formation_retreive_apc_niveau(
                     referentiel_competence_id, ue_info[1]
                 )
-            ue_id = sco_edit_ue.do_ue_create(ue_info[1])
+            # Note: si le code est indiqué "" dans le xml, il faut le conserver vide
+            # pour la comparaison ultérieure des formations XXX
+            ue_id = sco_edit_ue.do_ue_create(ue_info[1], allow_empty_ue_code=True)
             ue: UniteEns = db.session.get(UniteEns, ue_id)
             assert ue
             if xml_ue_id:
diff --git a/app/views/notes.py b/app/views/notes.py
index 43ea7933..7544e50f 100644
--- a/app/views/notes.py
+++ b/app/views/notes.py
@@ -824,7 +824,6 @@ def ue_clone():
     ue_id = int(request.form.get("ue_id"))
     ue = UniteEns.query.get_or_404(ue_id)
     ue2 = ue.clone()
-    db.session.add(ue2)
     db.session.commit()
     flash(f"UE {ue.acronyme} dupliquée")
     return flask.redirect(