Re: Self referencing composite datatype

Sameer Thakur 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?

In theory if you are using 9.1 or later you can first create the node type
and then alter it to include a children attribute with the self-referencing
type-array.

begin;

create type node as (r integer, s integer);
alter type node add attribute children node[];

end;

I'm running 9.0 so cannot readily test this at the moment.

David J.

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