arrays of rows and dblink

Torsten Förtsch wrote

Hi,

we have the ROW type and we have arrays. We also can create arrays of
rows like:

select array_agg(r)
from (values (1::int, 'today'::timestamp, 'a'::text),
(2, 'yesterday', 'b')) r(a,b,c);
array_agg
-------------------------------------------------------------------
{"(1,\"2014-04-30 00:00:00\",a)","(2,\"2014-04-29 00:00:00\",b)"}

Now I want to execute that query via dblink on a remote server. How do I
specify the result type?

select tb.* from dblink( 'dbname=postgres', $$
select array_agg(r)
from (values (1::int, 'today'::timestamp, 'a'::text),
$$) tb( WHAT DO I PUT HERE? )

Thanks,
Torsten

ISTM that you have to "CREATE TYPE ..." as appropriate then

... tb ( col_alias type_created_above[] )

There is only so much you can do with anonymous types (which is what the ROW
construct creates; ROW is not a type but an expression anchor - like
ARRAY[...]) that tells the parser how to interpret what follows.

David J.

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On 30/04/14 20:19, David G Johnston wrote:

ISTM that you have to "CREATE TYPE ..." as appropriate then

... tb ( col_alias type_created_above[] )

There is only so much you can do with anonymous types (which is what the ROW
construct creates; ROW is not a type but an expression anchor - like
ARRAY[...]) that tells the parser how to interpret what follows.

I thought so. Do I have to create the type in both databases or only on
the receiving site?

Thanks,
Torsten

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Torsten Förtsch wrote

On 30/04/14 20:19, David G Johnston wrote:

ISTM that you have to "CREATE TYPE ..." as appropriate then

... tb ( col_alias type_created_above[] )

There is only so much you can do with anonymous types (which is what the
ROW
construct creates; ROW is not a type but an expression anchor - like
ARRAY[...]) that tells the parser how to interpret what follows.

I thought so. Do I have to create the type in both databases or only on
the receiving site?

No idea but it would probably be a good idea to create the type on both
sides regardless of what is required.

David J.

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-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 04/30/2014 12:52 PM, Torsten F�rtsch wrote:

Hi,

we have the ROW type and we have arrays. We also can create arrays
of rows like:

select array_agg(r) from (values (1::int, 'today'::timestamp,
'a'::text), (2, 'yesterday', 'b')) r(a,b,c); array_agg
-------------------------------------------------------------------

{"(1,\"2014-04-30 00:00:00\",a)","(2,\"2014-04-29 00:00:00\",b)"}

Now I want to execute that query via dblink on a remote server. How
do I specify the result type?

select tb.* from dblink( 'dbname=postgres', $$ select array_agg(r)
from (values (1::int, 'today'::timestamp, 'a'::text), $$) tb( WHAT
DO I PUT HERE? )

select * from dblink('dbname=test',$$select array_agg(r) from (values
(1::int, 'today'::timestamp, 'a'::text), (2, 'yesterday', 'b'))
r(a,b,c)$$) as d(f text[]);
f
- -------------------------------------------------------------------
{"(1,\"2014-04-30 00:00:00\",a)","(2,\"2014-04-29 00:00:00\",b)"}
(1 row)

HTH,

Joe

- --
Joe Conway
credativ LLC: http://www.credativ.us
Linux, PostgreSQL, and general Open Source
Training, Service, Consulting, & 24x7 Support
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