Add a foriegn key constraint to to a sub type on an object table

Question

Hi,
I'm trying to set up a new table of an object type in our DB at work and on it I want to create a foreign key constraint on one of the attributes of one of the sub types
The table is called documents and is a table of document_ot
Definition:
create or replace
TYPE document_ot AS OBJECT (
-- ATTRIBUTES
created_date DATE,
created_by VARCHAR2( 32 ),
doc_id NUMBER,
-- CONSTRUCTORS
) NOT INSTANTIABLE NOT FINAL;
This type is extended by the type funding_certificates_ot
create or replace
TYPE funding_certificate_ot UNDER document_ot (
-- ATTRIBUTES
fc_prefix VARCHAR2( 2 ),
fc_sequence NUMBER,
fc_suffix VARCHAR2( 1 ),
fc_pr_id NUMBER,
-- CONSTRUCTORS
-- METHODS
) NOT FINAL;
I want to add a constraint to the to documents table that says that the funding_certificate_ot column fc_pr_id references pr_id in the table payruns.
I've managed to create an index on the fc_pr_id column using:
CREATE INDEX fc_pr_idx
ON documents d (treat (value(d) as funding_certificate_ot).fc_pr_id);
The code I thought I'd use for the foreign key constraint would be:
ALTER TABLE documents d
ADD CONSTRAINT doc_pr_fk FOREIGN KEY
treat (value(d) as funding_certificate_ot).fc_pr_id
REFERENCES payruns
(pr_id)
ENABLE;
But that doesn't work - would someone be able to give me the correct syntax please?
Many thanks

Answer 1

Hi,
I'm trying to set up a new table of an object type in our DB at work and on it I want to create a foreign key constraint on one of the attributes of one of the sub types
The table is called documents and is a table of document_ot
Definition:
create or replace
TYPE document_ot AS OBJECT (
-- ATTRIBUTES
created_date DATE,
created_by VARCHAR2( 32 ),
doc_id NUMBER,
-- CONSTRUCTORS
) NOT INSTANTIABLE NOT FINAL;
This type is extended by the type funding_certificates_ot
create or replace
TYPE funding_certificate_ot UNDER document_ot (
-- ATTRIBUTES
fc_prefix VARCHAR2( 2 ),
fc_sequence NUMBER,
fc_suffix VARCHAR2( 1 ),
fc_pr_id NUMBER,
-- CONSTRUCTORS
-- METHODS
) NOT FINAL;
I want to add a constraint to the to documents table that says that the funding_certificate_ot column fc_pr_id references pr_id in the table payruns.
I've managed to create an index on the fc_pr_id column using:
CREATE INDEX fc_pr_idx
ON documents d (treat (value(d) as funding_certificate_ot).fc_pr_id);
The code I thought I'd use for the foreign key constraint would be:
ALTER TABLE documents d
ADD CONSTRAINT doc_pr_fk FOREIGN KEY
treat (value(d) as funding_certificate_ot).fc_pr_id
REFERENCES payruns
(pr_id)
ENABLE;
But that doesn't work - would someone be able to give me the correct syntax please?
Many thanks