Re: Invalid Unicode escape value at or near "\u0000"

On 11/13/21 00:40, Thomas Munro wrote:
> On Sat, Nov 13, 2021 at 4:32 PM Japin Li <japinli@hotmail.com> wrote:
>> When I try to insert an Unicode "\u0000", there is an error $subject.
>>
>> postgres=# CREATE TABLE tbl (s varchar(10));
>> CREATE TABLE
>> postgres=# INSERT INTO tbl VALUES (E'\u0000');
>> ERROR:  invalid Unicode escape value at or near "\u0000"
>> LINE 1: INSERT INTO tbl VALUES (E'\u0000');
>>                                   ^
>>
>> "\u0000" is valid unicode [1], why not we cannot insert it?
> Yes, it is a valid codepoint, but unfortunately PostgreSQL can't
> support it because it sometimes deals in null terminated string, even
> though internally it does track string data and length separately.  We
> have to do that to use libc facilities like strcoll_r(), and probably
> many other things.
>
>

And it's documented at
<https://www.postgresql.org/docs/current/datatype-character.html>:


    The characters that can be stored in any of these data types are
    determined by the database character set, which is selected when the
    database is created. Regardless of the specific character set, the
    character with code zero (sometimes called NUL) cannot be stored.


cheers


andrew


--
Andrew Dunstan
EDB: https://www.enterprisedb.com