Omit external volume from DDL when not provided

Author: dlouseiro

dbt/adapters/snowflake/relation.py

@@ -213,10 +213,11 @@ def get_iceberg_ddl_options(self, config: RelationConfig) -> str:
             base_location += f"/{subpath}"
 
         iceberg_ddl_predicates: str = f"""
-        external_volume = '{config.get('external_volume')}'
         catalog = 'snowflake'
         base_location = '{base_location}'
         """
+        if external_volume := config.get("external_volume"):
+            iceberg_ddl_predicates += f"\nexternal_volume = '{external_volume}'"
         return textwrap.indent(textwrap.dedent(iceberg_ddl_predicates), " " * 10)
 
     def __drop_conditions(self, old_relation: "SnowflakeRelation") -> Iterator[Tuple[bool, str]]:

dbt/adapters/snowflake/relation_configs/catalog.py

@@ -66,6 +66,8 @@ def from_dict(cls, config_dict: Dict[str, Any]) -> Self:
         }
         if table_format := config_dict.get("table_format"):
             kwargs_dict["table_format"] = TableFormat(table_format)
+        if external_volume := config_dict.get("external_volume"):
+            kwargs_dict["external_volume"] = external_volume
         return super().from_dict(kwargs_dict)
 
     @classmethod