Add an option to show create table statement for postgre_fdw

[sunng87]

What type of enhancement is this?

API improvement

What does the enhancement do?

When using GreptimeDB tables in Postgres foreign data wrapper, it requires user to create a foreign table first. So user will need to:

1. get column names of GreptimeDB
2. get column types of GreptimeDB, that maps to Postgres types

CREATE FOREIGN TABLE ft_app_logs (
  ts TIMESTAMP,
  host VARCHAR,
  api_path VARCHAR,
  log_level VARCHAR,
  log VARCHAR
)
SERVER greptimedb
OPTIONS (table_name 'app_logs');

These steps can be tedious especially when user need to figure out mappings like double to double precision.

It can be helpful to offer an option to our show create table statement to dump this sql .

Implementation challenges

No response