Updates related to data file exports.

app/lib_general.py

@@ -382,6 +382,11 @@ def create_export_file(
     data_dataframe = pandas.DataFrame(data_dict_list)
     log.debug(data_dataframe)
 
+    missing_cols = [col for col in column_name_li if col not in data_dataframe.columns]
+    if missing_cols:
+        raise KeyError(f"The following columns are not found in the DataFrame: {', '.join(missing_cols)}")
+
+    # Need to deal with this error: KeyError("Not all names specified in 'columns' are found")
     try:
         if export_type == 'CSV':
             log.info('Saving dataframe to CSV file')
@@ -390,7 +395,7 @@ def create_export_file(
             tmp_file_path = os.path.join(subdir_path,filename_w_ext)
             data_dataframe.to_csv(
                 full_dest_path,
-                # na_rep='NULL',
+                na_rep='NULL',
                 columns=column_name_li,
                 index=False,
                 # errors='ignore',
@@ -403,7 +408,7 @@ def create_export_file(
             # This should ignore unknown columns
             data_dataframe.to_excel(
                 full_dest_path,
-                # na_rep='NULL',
+                na_rep='NULL',
                 columns=column_name_li,
                 index=False,
                 # engine='openpyxl',