diff --git a/backend/app/db/functions/recommendations_functions.py b/backend/app/db/functions/recommendations_functions.py
index 1864a330..2f85cbec 100644
--- a/backend/app/db/functions/recommendations_functions.py
+++ b/backend/app/db/functions/recommendations_functions.py
@@ -1,8 +1,9 @@
-from typing import List
-from sqlalchemy import text
-from sqlalchemy import insert, delete
+from typing import Any, List, Optional
+from sqlalchemy import text, insert, delete, select, update
 from sqlalchemy.orm import Session
 from sqlalchemy.exc import SQLAlchemyError
+from sqlmodel import Session
+
 from backend.app.db.models.recommendations import (
     PlanModel,
     Recommendation,
@@ -618,12 +619,26 @@ def clear_portfolio_in_batches(
 
 
 def get_plans_by_portfolio_id(portfolio_id: int) -> List[PlanModel]:
-    raise NotImplementedError
+    stmt = select(PlanModel).where(PlanModel.portfolio_id == portfolio_id)
+    with db_read_session() as session:
+        session_any: Any = session  # Typehint as Any to satisfy Pylance...
+        return session_any.exec(stmt).all()
 
 
-def get_scenario(scenario_id: int) -> ScenarioModel:
-    raise NotImplementedError
+def get_scenario(scenario_id: int) -> Optional[ScenarioModel]:
+    stmt = select(ScenarioModel).where(ScenarioModel.id == scenario_id)
+    with db_read_session() as session:
+        session_any: Any = session  # Typehint as Any to satisfy Pylance...
+        return session_any.exec(stmt).scalar_one_or_none()
 
 
 def set_plan_default(plan_id: int, is_default: bool) -> bool:
-    raise NotImplementedError
+    with db_read_session() as session:
+        stmt = (
+            update(PlanModel)
+            .where(PlanModel.id == plan_id)
+            .values(is_default=is_default)
+        )
+        result = session.exec(stmt)
+        session.commit()
+        return result.rowcount > 0