Re: Recursive FOREIGN KEY?

Joe Stump <joe(at)joestump(dot)net> writes:
> I had to insert the initial record and then add the foreign key
> restraint after inserting the initial record was created (0 being the
> first level of the category structure) -

Why? It worked fine for me without any workaround ...

regression=# CREATE TABLE categories (
regression(# categoryID integer PRIMARY KEY,
regression(# parentID integer REFERENCES categories (categoryID) ON DELETE CASCADE,
regression(# name text);
NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "categories_pkey" for table "categories"
CREATE TABLE
regression=# insert into categories values(0,0,'root');
INSERT 1349044 1
regression=# insert into categories values(1,2,'root');
ERROR: insert or update on table "categories" violates foreign key constraint "$1"
DETAIL: Key (parentid)=(2) is not present in table "categories".
regression=# insert into categories values(1,0,'root');
INSERT 1349046 1
regression=#

regards, tom lane