diff --git a/timesheet_block/models/timesheet.py b/timesheet_block/models/timesheet.py
index 6c28210..e39d216 100755
--- a/timesheet_block/models/timesheet.py
+++ b/timesheet_block/models/timesheet.py
@@ -41,7 +41,7 @@ class TimehseetBlock(models.Model):
         current_date = datetime.today().date()
         config = self.env['ir.config_parameter'].sudo()
         config_days_limit = float(config.get_param('timesheet_block.timesheet_edit_create_limit'))
-        entry_start_date = datetime.strptime(values['start_datetime'],"%Y-%m-%d %H:%M:%S").date()
+        entry_start_date = datetime.strptime(str(values['start_datetime']),"%Y-%m-%d %H:%M:%S").date()
         # entry_end_date = datetime.strptime(values['end_datetime'],"%Y-%m-%d %H:%M:%S").date()
         days = (current_date - entry_start_date).days
         employee_object = self.env['hr.employee'].search([('user_id', '=', self.env.uid)])
@@ -63,7 +63,7 @@ class TimehseetBlock(models.Model):
         current_date = datetime.today().date()
         if 'start_datetime' in record or 'end_datetime' in record or 'project_id' in record or 'sub_project' in record or 'task_id' in record or 'description' in record:
             if 'start_datetime' in record:
-                entry_start_date = datetime.strptime(record['start_datetime'],"%Y-%m-%d %H:%M:%S").date()
+                entry_start_date = datetime.strptime(str(record['start_datetime']),"%Y-%m-%d %H:%M:%S").date()
                 # entry_end_date = datetime.strptime(record['end_datetime'],"%Y-%m-%d %H:%M:%S").date()
             else:
                 res_start_date = str(self.start_datetime).split('.', 1)[0]
@@ -88,18 +88,33 @@ class TimehseetBlock(models.Model):
 
 
 
-    @api.onchange('end_datetime' ,'start_datetime')
-    def _onchange_end_datetime(self):
-        if self.end_datetime:
-            current_date = datetime.today().date()
-            end_date = datetime.strptime(str(self.end_datetime), "%Y-%m-%d %H:%M:%S").date()
-            if end_date > current_date:
-                raise AccessError('End date cannot be a future date!')
-        if self.end_datetime and self.start_datetime:
-            end_date = datetime.strptime(str(self.end_datetime), "%Y-%m-%d %H:%M:%S").date()
-            start_date = datetime.strptime(str(self.start_datetime), "%Y-%m-%d %H:%M:%S").date()
-            total_hours = (self.end_datetime - self.start_datetime).total_seconds() / 3600
-            self.unit_amount = total_hours
-            if start_date > end_date:
+    # @api.onchange('end_datetime' ,'start_datetime')
+    # def _check_end_datetime(self):
+    #     if self.end_datetime and self.start_datetime:
+    #         current_date = datetime.today().date()
+    #         end_date = datetime.strptime(str(self.end_datetime), "%Y-%m-%d %H:%M:%S").date()
+    #         start_date = datetime.strptime(str(self.start_datetime), "%Y-%m-%d %H:%M:%S").date()
+    #         if end_date > current_date:
+    #             self.end_datetime = False
+    #             self.start_datetime = False
+    #             raise AccessError('End date cannot be a future date!')
+    #         if start_date > end_date:
+    #             self.end_datetime = False
+    #             self.start_datetime = False
+    #             raise AccessError('End date should be greater than start date!')
+
+    @api.constrains('unit_amount')
+    def _check_unit_amount(self):
+        for rec in self:
+            if rec.unit_amount < 0.0:
                 raise AccessError('End date should be greater than start date!')
 
+    @api.constrains('end_datetime')
+    def _check_end_datetime(self):
+        current_date = datetime.today().date()
+        for rec in self:
+            if rec.end_datetime:
+                end_date = datetime.strptime(str(self.end_datetime), "%Y-%m-%d %H:%M:%S").date()
+                if end_date > current_date:
+                    raise AccessError('End date cannot be a future date!')
+