Use Dblink without column defination

Started by Chirag Karkeraover 3 years ago3 messages
#1Chirag Karkera
chiragkrkr102@gmail.com

Hi Team,

Appreciate your time to look into this.

To select from another database I try to use dblink or fdw extension of
Postgres, like this:

mesods =>CREATE EXTENSION dblink;

CREATE EXTENSION

mesods => CREATE EXTENSION postgres_fdw;

CREATE EXTENSION

mesods=> select dblink_connect('conn_db_link','foreign_server') ;

dblink_connect

----------------

OK

(1 row)

mesods=> select * from dblink('foreign_server','select * from ods_sch.emp')
AS x(a int,b text);

a | b

---+---------

1 | Gohan

1 | Piccolo

1 | Tien

(3 rows)

This works fine when I specify which columns I want to select.

Is there something that postgres has without specifying the column names we
can fetch the data from dblink.

Awaiting your reply.

Thank you.

Regards,

Chirag Karkera

#2Chirag Karkera
chiragkrkr102@gmail.com
In reply to: Chirag Karkera (#1)
Re: Use Dblink without column defination

Hi Team,

Any update on this?

Thank You.

Regards,
Chirag Karkera

On Mon, 23 May, 2022, 1:46 pm Chirag Karkera, <chiragkrkr102@gmail.com>
wrote:

Show quoted text

Hi Team,

Appreciate your time to look into this.

To select from another database I try to use dblink or fdw extension of
Postgres, like this:

mesods =>CREATE EXTENSION dblink;

CREATE EXTENSION

mesods => CREATE EXTENSION postgres_fdw;

CREATE EXTENSION

mesods=> select dblink_connect('conn_db_link','foreign_server') ;

dblink_connect

----------------

OK

(1 row)

mesods=> select * from dblink('foreign_server','select * from
ods_sch.emp') AS x(a int,b text);

a | b

---+---------

1 | Gohan

1 | Piccolo

1 | Tien

(3 rows)

This works fine when I specify which columns I want to select.

Is there something that postgres has without specifying the column names
we can fetch the data from dblink.

Awaiting your reply.

Thank you.

Regards,

Chirag Karkera

#3Peter Eisentraut
peter.eisentraut@enterprisedb.com
In reply to: Chirag Karkera (#1)
Re: Use Dblink without column defination

On 23.05.22 10:16, Chirag Karkera wrote:

mesods=> select * from dblink('foreign_server','select * from
ods_sch.emp') AS x(a int,b text);

 a |    b

---+---------

 1 | Gohan

 1 | Piccolo

 1 | Tien

(3 rows)

This works fine when I specify which columns I want to select.

Is there something that postgres has without specifying the column names
we can fetch the data from dblink.

Not in dblink. You could use foreign-data wrappers, which have a
different interface, which you might like better.