perf: remove redundant COUNT query and use bulk insert for CSV imports

app/routes/data.py

@@ -17,16 +17,17 @@ def manage_data():
             try:
                 csv_data = csv.reader(StringIO(file.read().decode('utf-8')))
                 next(csv_data)  # Skip the header row
+                readings_to_add = []
                 for row in csv_data:
                     timestamp, systolic, diastolic, heart_rate = row
-                    reading = Reading(
+                    readings_to_add.append(Reading(
                         user_id=current_user.id,
                         timestamp=datetime.strptime(timestamp, '%Y-%m-%d %H:%M:%S'),
                         systolic=int(systolic),
                         diastolic=int(diastolic),
                         heart_rate=int(heart_rate),
-                    )
-                    db.session.add(reading)
+                    ))
+                db.session.bulk_save_objects(readings_to_add)
                 db.session.commit()
                 flash('Data imported successfully!', 'success')
             except Exception as e: