Anyone recognise this error from PL/pgSQL?

Hi,

I'm trying my first PL/pgSQL code to trap foreign key errors. Before inserting
into the table "Exon", I wish to be sure that a foreign key, 'zhvtID', exists in
the table 'zhvt'. Sounds simple...

This is the code I use:

CREATE FUNCTION exon_foreign_keys() RETURNS opaque AS '
DECLARE     zhvt_row zhvt%ROWTYPE;
BEGIN   IF NEW.zhvtID ISNULL THEN   RAISE EXCEPTION ''zhvtID can not be NULL'';   END IF;
   SELECT * INTO zhvt_row FROM zhvt         WHERE zhvtID=NEW.zhvtID;   IF NOT FOUND THEN         RAISE EXCEPTION
''zhvtID=% is not in TABLE zhvt'' , NEW.zhvtID;   END IF;
 
END;
' LANGUAGE 'plpgsql';

And this is the trigger I create to call the code upon insert:

CREATE TRIGGER check_exon_FK BEFORE INSERT OR UPDATE ON exonFOR EACH ROW EXECUTE PROCEDURE exon_foreign_keys();

And this is the error I get when I try to insert anything, regardless of whether
the foreign key exists or not:

zhvt=> insert into exon (zhvtID, number, start, stop, iscomplement)
zhvt-> values (1, 1, 1, 100, 't');
ERROR:  There is no operator '=$' for types 'int4' and 'int4'       You will either have to retype this query using an
explicitcast,       or you will have to define the operator using CREATE OPERATOR
 

If I drop the trigger, the error goes away.

Any ideas?

Mark

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Mark Dalphin                          email: mdalphin@amgen.com
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