diff --git a/advlabdb/models.py b/advlabdb/models.py
index fb332e7..ffbc72f 100644
--- a/advlabdb/models.py
+++ b/advlabdb/models.py
@@ -501,20 +501,20 @@ class ExperimentMark(db.Model):
     oral_mark = db.Column(
         db.Integer,
         db.CheckConstraint(f"oral_mark >= {MIN_MARK}"),
-        db.CheckConstraint(f"oral_mark <= {MIN_MARK}"),
+        db.CheckConstraint(f"oral_mark <= {MAX_MARK}"),
         nullable=True,
     )
     protocol_mark = db.Column(
         db.Integer,
         db.CheckConstraint(f"oral_mark >= {MIN_MARK}"),
-        db.CheckConstraint(f"oral_mark <= {MIN_MARK}"),
+        db.CheckConstraint(f"oral_mark <= {MAX_MARK}"),
         nullable=True,
     )
 
     final_experiment_mark = db.Column(
         db.Integer,
         db.CheckConstraint(f"oral_mark >= {MIN_MARK}"),
-        db.CheckConstraint(f"oral_mark <= {MIN_MARK}"),
+        db.CheckConstraint(f"oral_mark <= {MAX_MARK}"),
         onupdate=final_experiment_mark_update,
         nullable=True,
     )