Re: [SQL] foreign key implementation

"Pausas Fuentes, Jaume" wrote:
>Hi
>
>Anybody have an implementation of the sql foreign key?
>
>Reading the manual it says that I must use the create trigger command
>but how to implement a procedure to do what foreing key does?

You need the refint package out of contrib.

Then use commands like these:

create database bray;
\connect bray

-- refint functions (from postgresql-contrib package). These are
-- needed until foreign keys are implemented in PostgreSQL
\i contrib/spi/refint.sql

create table area
(
id char(2) primary key,
name text not null,
vat_class char(1) default 'S'
);

create trigger area_fref
before DELETE or UPDATE on area
for each row execute procedure
check_foreign_key (1, 'restrict', 'id',
'customer', 'area'
);

create table customer
(
acs_code char(8),
...
area char(2) references area (id),
...
);

create trigger customer_pkref2
before INSERT or UPDATE on customer
for each row execute procedure
check_primary_key ('area', 'area', 'id');

--
Oliver Elphick Oliver(dot)Elphick(at)lfix(dot)co(dot)uk
Isle of Wight http://www.lfix.co.uk/oliver
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