On Wed, Aug 7, 2013 at 4:57 AM, Sameer Thakur <samthaku...@gmail.com> wrote:
> Hello, > I wanted to create a composite datatype to represent a Node. So it would > have a few attributes and an array of type Node which is the children of > this node. > create type Node as (r integer, s integer, children Node []); > But i get error type Node[] does not exist. I understand that Node is not > defined hence the error. > But how do i get around this problem? > What exactly are you trying to accomplish? I can think of a number of ways. For example, suppose we have a table like: create table node ( id int primary key, parent int references node(id), content text not null ); We could create a function like this: CREATE FUNCTION children(node) RETURNS node[] LANGUAGE SQL AS $$ SELECT array_agg(node) FROM node WHERE parent=$1.id; $$; Then we could still do: select n.children FROM node n WHERE id = 123; Note that causes two separate scans, but should work. Best Wishes, Chris Travers > > regards > Sameer > -- Best Wishes, Chris Travers Efficito: Hosted Accounting and ERP. Robust and Flexible. No vendor lock-in. http://www.efficito.com/learn_more.shtml
