Re: referential integrity violation

On Mon, 21 Oct 2002 mk(at)fashaf(dot)co(dot)za wrote:

> I have tried '' , undef , 'NULL' , 'null' non of them seem to work?
>
> any idea how to submit a NULL value with perl?
>

Okay, let's take a step back to view the slightly larger picture rather than
the little detail...

With a design such as:

create table t1 (
i int primary key
);

create table t2 (
i int primary key,
t text,
a int references t1 (a)
);

your perl code should be submitting a string such as, note the lack of quotes
around the null:

insert into mytable values ( 23, 'my text', NULL )

i.e.

use Pg;

# connect to server etc.

$conn->exec("insert into mytable values ( 23, 'my text', NULL )");

# error check etc.

Hope this helps.

> > > On Fri, 18 Oct 2002 at 10:34:31 -0400, Darren Ferguson wrote:
> > > > What is happening is that you are trying to insert and id for slip
> > > > printer into the TABLE pc but the id does not exist in the slip printer
> > > > table.
> > > >
> > > > Since you have slip_printer in pc table and you specified that it
> > > > references the slip_printer table id then you must have an id in slip
> > > > printer for it to insert into the pc table unless you insert a null value
> > > > since you did not specify the constraint on the table
> > > >
> > > > HTH
> > > >
> > > > On Fri, 18 Oct 2002 mk(at)fashaf(dot)co(dot)za wrote:
> > > >
> > > > > Hi guys
> > > > >
> > > > > I have created a Pg DB, Ive included 2 of the tables.
> > > > > When inserting non NULL values everything works just fine,
> > > > > but when i want to leave a table empty i get the following error:
> > > > >
> > > > > EXEC: ERROR: referential integrity violation - key referenced from pc not found in slip_printer
> > > > >
> > > > > Im recieving the information from a Perl CGI form that is filled in and then INSERT it using perl DBI
> > > > >
> > > > > If any more information is needed please let me know. As far as i know i should be allowed to have null.
> > > > >
> > > > > TIA
> > > > > Merritt
> > > > >
> > > > > CREATE TABLE slip_printer (
> > > > > id SERIAL PRIMARY KEY,
> > > > > make VARCHAR(256) NOT NULL,
> > > > > model VARCHAR(256) NOT NULL,
> > > > > UNIQUE (make, model)
> > > > > );
> > > > >
> > > > > CREATE TABLE pc (
> > > > > id SERIAL PRIMARY KEY,
> > > > > store INTEGER REFERENCES store (id) NOT NULL,
> > > > > cpu_type INTEGER REFERENCES cpu_type (id) NOT NULL,
> > > > > cpu_mhz INTEGER REFERENCES cpu_mhz (id) NOT NULL,
> > > > > memory_type INTEGER REFERENCES memory_type (id) NOT NULL,
> > > > > memory_amount INTEGER, /* amount of chips/sticks, not size in MB */
> > > > > hdd INTEGER REFERENCES hdd (id),
> > > > > hdd_serial VARCHAR(256),
> > > > > monitor INTEGER REFERENCES monitor (id) NOT NULL,
> > > > > slip_printer INTEGER REFERENCES slip_printer (id),
> > > > > report_printer INTEGER REFERENCES report_printer (id),
> > > > > cash_drawer INTEGER REFERENCES cash_drawer (id) NOT NULL,
> > > > > scanner INTEGER REFERENCES scanner (id) NOT NULL,
> > > > > ups INTEGER REFERENCES ups (id),
> > > > > modem INTEGER REFERENCES modem (id)
> > > > > );
> > > > >
> > > >

--
Nigel J. Andrews