Обсуждение: a set of key/value pairs

Does anyone have a specific example of how to:
     1) create a variable that is a set or array of key value pairs?
     2) how to populate each element of the array (each element being a
key / value pair)
     3) how to iterate through the list or array retrieving each
key/value pair?

Please do not point me to this doc:
     http://developer.postgresql.org/pgdocs/postgres/hstore.html

What I am looking for is an example as listed in 1..3 above, and that is
not provided in the doc.

Regards,


J.V.

On 10/20/11 11:53 AM, J.V. wrote:
> Does anyone have a specific example of how to:
>     1) create a variable that is a set or array of key value pairs?
>     2) how to populate each element of the array (each element being a
> key / value pair)
>     3) how to iterate through the list or array retrieving each
> key/value pair?

in what programming language?     in SQL, there aren't 'variables',
there are relations, and you don't 'iterate', you query.



--
john r pierce                            N 37, W 122
santa cruz ca                         mid-left coast

On Thu, Oct 20, 2011 at 1:53 PM, J.V. <jvsrvcs@gmail.com> wrote:
> Does anyone have a specific example of how to:
>    1) create a variable that is a set or array of key value pairs?
>    2) how to populate each element of the array (each element being a key /
> value pair)
>    3) how to iterate through the list or array retrieving each key/value
> pair?

create type pair_t as (key text, value text);

select array[('a', '123'), ('b', '234')]::pair_t[];

select (unnest(array[('a', '123'), ('b', '234')]:: pair_t[])).*;

merlin