diff --git a/pyproject.toml b/pyproject.toml
index 2b28861..0ba6d98 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "shaped-target-clickhouse"
-version = "0.1.9"
+version = "0.1.10"
 description = "`target-clickhouse` is a Singer target for clickhouse, built with the Meltano Singer SDK."
 readme = "README.md"
 authors = ["Ben Theunissen"]
diff --git a/target_clickhouse/sinks.py b/target_clickhouse/sinks.py
index f3e30dd..5b73b1d 100644
--- a/target_clickhouse/sinks.py
+++ b/target_clickhouse/sinks.py
@@ -175,6 +175,10 @@ def _pre_validate_for_string_type(self, record: dict) -> dict:
         for key, value in record.items():
             # Checking if the schema expects a string for this key.
             expected_type = self.schema.get("properties", {}).get(key, {}).get("type")
+            if expected_type is None:
+                continue
+            if not isinstance(expected_type, list):
+                expected_type = [expected_type]
             if "string" in expected_type and not isinstance(value, str):
                 # Convert the value to string if it's not already a string.
                 record[key] = (