[BUG][cnosdb fdw]If all fields in the external table are missing, reading and writing will fail.

[Benxiaohai001]

Describe the bug

If all fields in the external table are missing, reading and writing will fail.

To Reproduce

cnosdb-cli

CREATE TABLE air (visibility DOUBLE,temperature DOUBLE,pressure DOUBLE,TAGS(station));

gsql

openGauss=# create foreign table air (time timestamp, station text) server cnosdb_server options (tenant 'cnosdb', database 'public');
CREATE FOREIGN TABLE
openGauss=# INSERT INTO air (TIME, station) VALUES (now(), 'XiaoMaiDao1');
ERROR:  Fail to request remote server: sql: INSERT INTO public.air(time, station) VALUES (TIMESTAMP '2024-04-19 18:20:35.46244', 'XiaoMaiDao1'), reason: http status code: 422 Unprocessable Entity, response text: {"error_code":"020002","error_message":"Fields can't be empty"}
openGauss=#

Expected behavior

No response

Additional context

No response

[Kree0]

Because of the difficulty of coding, users now must check that the schema of the table in opengauss is the same as the schema of the table in cnosdb.