Better integration of sqlite3 database

backend/app/database.py

@@ -1,15 +1,16 @@
+from sqlalchemy.orm import Session
 from sqlalchemy import create_engine
 from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.orm import sessionmaker
 
-DATABASE_URL = "sqlite:///./test.db"
+SQLALCHEMY_DATABASE_URL = "sqlite:///./test.db"
 
-# Database setup
-engine = create_engine(DATABASE_URL, connect_args={"check_same_thread": False})
+engine = create_engine(SQLALCHEMY_DATABASE_URL, connect_args={"check_same_thread": False})
 SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
 
 Base = declarative_base()
 
+
 # Dependency
 def get_db():
     db = SessionLocal()
@@ -18,7 +19,21 @@ def get_db():
     finally:
         db.close()
 
-# Initialize the database
+
 def init_db():
-    import app.models  # Import all models here for metadata.create_all() to recognize them
-    Base.metadata.create_all(bind=engine)
+    # Import inside function to avoid circular dependency
+    from app import models  
+    Base.metadata.create_all(bind=engine)
+
+
+def load_sample_data(session: Session):
+    # Import inside function to avoid circular dependency
+    from app.data import contacts, return_addresses, dewars, proposals, shipments
+
+    from app import models  # Ensure these imports are correct
+
+    if session.query(models.ContactPerson).first():
+        return
+
+    session.add_all(contacts + return_addresses + dewars + proposals + shipments)
+    session.commit()