model class update total cal fields all model

app/models/tr_ex_client_model.py

@@ -1,14 +1,11 @@
 from app import db
 from datetime import datetime
+from sqlalchemy import event
 
 class TrenchExcavationClient(db.Model):
     __tablename__ = "tr_ex_client"
 
     id = db.Column(db.Integer, primary_key=True)
-    #  Foreign Key to Subcontractor table
-    # subcontractor_id = db.Column(db.Integer, db.ForeignKey("subcontractors.id"), nullable=False)
-    # Relationship for easy access (subcontractor.subcontractor_name)
-    # subcontractor = db.relationship("Subcontractor", backref="tr_ex_records")
 
     # Basic Fields
     RA_Bill_No=db.Column(db.String(500))
@@ -86,3 +83,19 @@ class TrenchExcavationClient(db.Model):
     
     def serialize(self):
             return {c.name: getattr(self, c.name) for c in self.__table__.columns}
+
+
+# ==========================================
+# AUTO CALCULATE GRAND TOTAL
+# ==========================================
+
+def calculate_trench_client_total(mapper, connection, target):
+    total = 0
+    for column in target.__table__.columns:
+        if column.name.endswith("_total"):
+            total += getattr(target, column.name) or 0
+    target.Total = total
+
+
+event.listen(TrenchExcavationClient, "before_insert", calculate_trench_client_total)
+event.listen(TrenchExcavationClient, "before_update", calculate_trench_client_total)