diff --git a/backend/src/playlist/sql.py b/backend/src/playlist/sql.py
index c7440ca..0248166 100644
--- a/backend/src/playlist/sql.py
+++ b/backend/src/playlist/sql.py
@@ -20,12 +20,10 @@ from playlist import models
 # Initialize asynchronous logger
 logger = aiologger.Logger.with_default_handlers(name="sql_logger")
 
-engine = sqlalchemy.ext.asyncio.create_async_engine(env.DATABASE_URL, echo=True)
+_engine = sqlalchemy.ext.asyncio.create_async_engine(env.DATABASE_URL, echo=True)
 
-mapper_registry = sqlalchemy.orm.registry()
-
-async_session_maker = sqlalchemy.orm.sessionmaker(
-    engine, class_=sqlalchemy.ext.asyncio.AsyncSession, expire_on_commit=False
+_async_session_maker = sqlalchemy.orm.sessionmaker(
+    _engine, class_=sqlalchemy.ext.asyncio.AsyncSession, expire_on_commit=False
 )
 
 
@@ -88,6 +86,8 @@ def _coro_db_logger(func: Sessionizable) -> Sessionizable:
             await kwargs["session"].rollback()
             raise
 
+    return wrapper
+
 
 def _async_gen_db_logger(func: Sessionizable) -> Sessionizable:
     @functools.wraps(func)
@@ -108,13 +108,15 @@ def _async_gen_db_logger(func: Sessionizable) -> Sessionizable:
             await kwargs["session"].rollback()
             raise
 
+    return wrapper
+
 
 def sessionize(func: Sessionizable) -> Sessionizable:
     """Decorator that ensures a database session is available to an async function or generator.
 
     This decorator automatically injects a `session` of type sqlalchemy.ext.asyncio.AsyncSession
     into the decorated function if one is not provided. If the `session` keyword argument is
-    missing or set to None, a new session is created using the async_session_maker and passed to
+    missing or set to None, a new session is created using the _async_session_maker and passed to
     the function. If a session is already provided when the function is called, it uses the
     existing session.
 
@@ -168,7 +170,7 @@ def sessionize(func: Sessionizable) -> Sessionizable:
                 logged_func = _coro_db_logger(func)
 
                 if kwargs["session"] is None:
-                    async with async_session_maker as kwargs["session"]:
+                    async with _async_session_maker() as kwargs["session"]:
                         return await logged_func(*args, **kwargs)
                 else:
                     return await logged_func(*args, **kwargs)
@@ -186,7 +188,7 @@ def sessionize(func: Sessionizable) -> Sessionizable:
 
                 logged_func = _async_gen_db_logger(func)
                 if kwargs["session"] is None:
-                    async with async_session_maker as kwargs["session"]:
+                    async with _async_session_maker() as kwargs["session"]:
                         async for element in logged_func(*args, **kwargs):
                             yield element
                 else:
@@ -209,8 +211,8 @@ def sessionize(func: Sessionizable) -> Sessionizable:
 async def init_db() -> None:
     """Create all tables asynchronously."""
     try:
-        async with engine.begin() as conn:
-            await conn.run_sync(mapper_registry.metadata.create_all)
+        async with _engine.begin() as conn:
+            await conn.run_sync(models.mapper_registry.metadata.create_all)
             await logger.info("Database tables created.")
     except Exception as e:
         await logger.error(f"Failed to create tables: {e}")
@@ -219,8 +221,8 @@ async def init_db() -> None:
 async def drop_db() -> None:
     """Drop all tables asynchronously for clean slate testing or teardown."""
     try:
-        async with engine.begin() as conn:
-            await conn.run_sync(mapper_registry.metadata.drop_all)
+        async with _engine.begin() as conn:
+            await conn.run_sync(models.mapper_registry.metadata.drop_all)
             await logger.info("Database tables dropped.")
     except Exception as e:
         await logger.error(f"Failed to drop tables: {e}")