presto-cassandra/src/main/java/io/prestosql/plugin/cassandra/NativeCassandraSession.java/NativeCassandraSession/checkColumnNames
class NativeCassandraSession:    private static void checkColumnNames(List<ColumnMetadata> columns)
    {
        Map<String, ColumnMetadata> lowercaseNameToColumnMap = new HashMap<>();
        for (ColumnMetadata column : columns) {
            String lowercaseName = column.getName().toLowerCase(ENGLISH);
            if (lowercaseNameToColumnMap.containsKey(lowercaseName)) {
                throw new PrestoException(
                        NOT_SUPPORTED,
                        format("More than one column has been found for the case insensitive column name: %s -> (%s, %s)",
                                lowercaseName, lowercaseNameToColumnMap.get(lowercaseName).getName(), column.getName()));
            }
            lowercaseNameToColumnMap.put(lowercaseName, column);
        }
    }