diff --git a/src/accounting/database.py b/src/accounting/database.py
index 96ad6e6..652763b 100644
--- a/src/accounting/database.py
+++ b/src/accounting/database.py
@@ -25,7 +25,7 @@ time.
 
 from flask_sqlalchemy import SQLAlchemy
 
-db: SQLAlchemy
+db: SQLAlchemy = SQLAlchemy()
 """The database instance."""
 
 
diff --git a/src/accounting/utils/user.py b/src/accounting/utils/user.py
index dae6739..1d2a243 100644
--- a/src/accounting/utils/user.py
+++ b/src/accounting/utils/user.py
@@ -72,9 +72,9 @@ class AbstractUserUtils(t.Generic[T], ABC):
 
 __user_utils: AbstractUserUtils
 """The user utilities."""
-user_cls: t.Type[Model]
+user_cls: t.Type[Model] = Model
 """The user class."""
-user_pk_column: sa.Column
+user_pk_column: sa.Column = sa.Column(sa.Integer)
 """The primary key column of the user class."""