This function returns a   string output stream
    initialized to contain the text of the file or its segment, on local file system path
    relative to the server@s working directory.file_to_string_output can handle longer
    files than
    file_to_string
    and the resulting string output, if too long to be converted into
    a varchar, can be stored inside a blob.Access controls in the server configuration file apply. An attempt
    to access a file in a directory where access is not explicitly allowed will signal an error.