pg_put_line() sends a
NULL-terminated string to the PostgreSQL backend server. This
is useful for example for very high-speed inserting of data
into a table, initiated by starting a PostgreSQL
copy-operation. That final NULL-character is added
automatically. 成功回傳TRUE失敗回傳FALSE。
注: The application must explicitly send the two characters "\." on the last line to indicate to the backend that it has finished sending its data.
See also pg_end_copy().