diff --git a/app/models/formsemestre.py b/app/models/formsemestre.py
index f02a19c75e..148d9c8714 100644
--- a/app/models/formsemestre.py
+++ b/app/models/formsemestre.py
@@ -325,10 +325,15 @@ class NotesSemSet(db.Model):
     sem_id = db.Column(db.Integer, nullable=True, default=None)
 
 
-# Association:
+# Association: many to many
 notes_semset_formsemestre = db.Table(
     "notes_semset_formsemestre",
     db.Column("formsemestre_id", db.Integer, db.ForeignKey("notes_formsemestre.id")),
-    db.Column("semset_id", db.Integer, db.ForeignKey("notes_semset.id")),
+    db.Column(
+        "semset_id",
+        db.Integer,
+        db.ForeignKey("notes_semset.id", ondelete="CASCADE"),
+        nullable=False,
+    ),
     db.UniqueConstraint("formsemestre_id", "semset_id"),
 )
diff --git a/migrations/versions/a217bf588f4c_scodoc_9_0_13_essai_cascade.py b/migrations/versions/a217bf588f4c_scodoc_9_0_13_essai_cascade.py
new file mode 100644
index 0000000000..3e0c53b5e3
--- /dev/null
+++ b/migrations/versions/a217bf588f4c_scodoc_9_0_13_essai_cascade.py
@@ -0,0 +1,36 @@
+"""ScoDoc 9.0.13: essai cascade
+
+Revision ID: a217bf588f4c
+Revises: f73251d1d825
+Create Date: 2021-09-10 21:44:34.947317
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = 'a217bf588f4c'
+down_revision = 'f73251d1d825'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.alter_column('notes_semset_formsemestre', 'semset_id',
+               existing_type=sa.INTEGER(),
+               nullable=False)
+    op.drop_constraint('notes_semset_formsemestre_semset_id_fkey', 'notes_semset_formsemestre', type_='foreignkey')
+    op.create_foreign_key(None, 'notes_semset_formsemestre', 'notes_semset', ['semset_id'], ['id'], ondelete='CASCADE')
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_constraint(None, 'notes_semset_formsemestre', type_='foreignkey')
+    op.create_foreign_key('notes_semset_formsemestre_semset_id_fkey', 'notes_semset_formsemestre', 'notes_semset', ['semset_id'], ['id'])
+    op.alter_column('notes_semset_formsemestre', 'semset_id',
+               existing_type=sa.INTEGER(),
+               nullable=True)
+    # ### end Alembic commands ###