diff --git a/src/dbally/views/exposed_functions.py b/src/dbally/views/exposed_functions.py
index 481052f7..1f35de15 100644
--- a/src/dbally/views/exposed_functions.py
+++ b/src/dbally/views/exposed_functions.py
@@ -1,7 +1,9 @@
 import re
+import typing_extensions as type_ext
 from dataclasses import dataclass
 from typing import _GenericAlias  # type: ignore
 from typing import Optional, Sequence, Type, Union
+from inspect import isclass
 
 from dbally.context.context import BaseCallerContext
 from dbally.similarity import AbstractSimilarityIndex
@@ -12,15 +14,22 @@ def parse_param_type(param_type: Union[type, _GenericAlias]) -> str:
     Parses the type of a method parameter and returns a string representation of it.
 
     Args:
-        param_type: type of the parameter
+        param_type: Type of the parameter.
 
     Returns:
-        str: string representation of the type
+        A string representation of the type.
     """
-    if param_type in {int, float, str, bool, list, dict, set, tuple}:
+
+    # TODO consider using hasattr() to ensure correctness of the IF's below
+    if isclass(param_type):
         return param_type.__name__
+
+    if type_ext.get_origin(param_type) is Union:
+        args_str_repr = ', '.join(parse_param_type(arg) for arg in type_ext.get_args(param_type))
+        return f"Union[{args_str_repr}]"
+
     if param_type.__module__ == "typing":
-        return re.sub(r"\btyping\.", "", str(param_type))
+        return param_type._name
 
     return str(param_type)