ColumnOptions.Builder columnOptions = ColumnOptions.newBuilder();
columnOptions.setNullForField(forField);
priorField = null;
if (priorMessage != null) {
for (FieldDescriptorProto field : priorMessage.getFieldList()) {
FieldOptions options = field.getOptions();
if ((options != null) &&
(options.hasExtension(ColumnOptions.fdbsql))) {
ColumnOptions coptions = options.getExtension(ColumnOptions.fdbsql);
if (coptions.hasNullForField() &&
(coptions.getNullForField() == forField)) {
priorField = field;
break;
}