Problem with Insert rules: using nextval: get schema *new* does not exist and other oddities

I am trying to see if it is possible to use rules to create complex
updateable views covering two or more tables. Initially I created two
test tables: one to hold CD names (cathyscds) and one to hold the track
names/numbers/times for each cd (cathystracks) using the following SQL:

CREATE TABLE cathyscds
( cdname varchar,
cdartist varchar,
cdid int4)
CREATE TABLE cathystracks
( cdid int4,
tracknumber int4,
trackname varchar,
tracktime float4)

I want views that would show the tracknames/times/numbers as arrays. I
wrote a simple aggregate function makearray (basically copying the toarray
example in the documentation), and created the view cdall: using SQL:

CREATE OR REPLACE VIEW cdall as
SELECT cdname, cdid,
(SELECT makeArray (tracknumber) from cathystracks WHERE
cathystracks.cdid = cathyscds.cdid)
AS numbers,
(SELECT makeArray (trackname) from cathystracks WHERE
cathystracks.cdid = cathyscds.cdid)
AS names,
(SELECT makeArray (tracktime) from cathystracks WHERE
cathystracks.cdid = cathyscds.cdid)
AS times
FROM cathyscds;

This works fine. However, I hit lots of problems trying to create an
Insert rule that would allow us to do something like:-
INSERT INTO cdall (cdname, names) VALUES ('cd name', '{track1 name,
track2 name}');

The function must create the PK cdid and put one row into the cathyscds
table, and zero,one or more rows into the cathystracks table.

I wrote a simple function (arrayToTable) to convert arrays to tables, to
support this. This works fine stand-alone.
I created a sequence cd_seq to give the next cdid numbers.
I tried the rule:

CREATE OR REPLACE RULE insert_cdall AS ON INSERT TO cdall DO INSTEAD (
select nextval ('cd_seq') INTO new.cdid;
insert into cathyscds (cdid, cdname) VALUES (new.cdid, new.cdname);
insert into cathystracks (trackname, cdid)
select arrayToTable (new.names), currval ('cd_seq') as cdid;
);

Which I think should work. However, the 'select nextval...' statement
appears in pgadmin under the Rules section as "select nextval ('cd_seq')
as nextval;" which seems odd. It fails: gives error 'schema *new* does
not exist. Why is this?

If I get round this problem by using nextval and currval then I get
problems that I cannot get round. The above SQL gives error: function
expression in FROM may not refer to other relations of same query level. I
found a discussion thread 'nonexistent new relation in some places of
rules' that hints that this is because the "select * from arrayToTable
(new.names)" is being expanded into " select * from new, arrayToTable
(new.names) ". Is this so, and if so, how do I get round it. Or should I
give up and use functions instead?

We are using Postgres 7.4.1. on a Windows 2000 server. If you need the
function code to help, please ask.

Thanks in advance
Cathy Hemsley

:.________________
CONFIDENTIALITY : This e-mail and any attachments are confidential and
may be privileged. If you are not a named recipient, please notify the
sender immediately and do not disclose the contents to another person, use
it for any purpose or store or copy the information in any medium.