Re: Object ID reference

Alex,

Most of the Object Relation Mapping I have seen get the id from a
special mechanism, so they know it before hand?

FYI oid's are not guaranteed to be unique in Postgres.

Dave

-----Original Message-----
From: pgsql-hackers-owner(at)postgresql(dot)org
[mailto:pgsql-hackers-owner(at)postgresql(dot)org] On Behalf Of Debian User
Sent: Friday, March 08, 2002 3:42 PM
To: pgsql-hackers(at)postgresql(dot)org
Subject: [HACKERS] Object ID reference

Hi I'm new to the list, and I'm new to the PostgreSQL also. But I have
been using Object Relation Mapping for a period of time. I would like to
put native binding with PostgreSQL . It is fairly easy to read and write
Object into the relayed table e.g.

create table base (
myname text,
unique( myname )
);

create table child (
myfather base,
myname text
);

INSERT INTO base ( myname ) Values ( 'alex' ) ;
INSERT 56578 1 <<---- oid
INSERT INTO child ( myfather, myname ) values ( 56578::base, 'alexbaby'
); INSERT 56579 1 <<---- oid

However, there is no way to get the value back in the WHERE clause.
because the return type is 'base' but the value output ( correct me if
I'm wrong from digging the source by hand ) is actually oid returns
int4 from internal seteval() function. select * from child; myfather
myname
-------------------
56578 alexbaby

It could be a easy fix in the jdbc, or c to match the seteval(base.oid)
with int4.[string, string] compare, but then I need to loop through the
full Record Set by hand to get the data. is there a possible way to do
some function to convert the TYPE 'base' to oid or int4 or string? so I
can do something like this

SELECT * from child where myfather=56578::base;

or how am I getting internal seteval to work right with the return set
from a custom function. I really want to see this coming out right...
thanks a lot. Alex

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