On 2009-12-28, JORGE MALDONADO <jorgemal1960@gmail.com> wrote:
> I am developing an app in which there are 2 tables: a parent and a child.
> The difference is that, in my case, the child table is generated first and,
> if the user decides to keep the information then a record is generated in
> the parent table and the child table is connected to its parent. The field
> in the child table that connects to its parent is temporarily filled with a
> value of -1. The user who types the information may decide to keep or not
> the records in the child table and it is at this time when a record in the
> parent table is generated or not. Meanwhile, the records in the child table
> have a tamporary value of -1 in the field that will connect to its parent
> table and this causes me not to be able to define a foreign key.
> Please advice.
One fix is to use NULL instead of -1
Another is to make the connstraint DEFERRABLE INITIALLY DEFERRED and
create the child records inside a transaction not COMMITing the
tranaction until thwey have been UPDATEd with the correct foreign key
value,
A third is to create a record in the parent table with a key of -1