On 08/23/2016 10:29 AM, David G. Johnston wrote:
On Tue, Aug 23, 2016 at 1:24 PM, Adrian Klaver
<adrian.klaver@xxxxxxxxxxx <mailto:adrian.klaver@xxxxxxxxxxx>>wrote:
use ALTER TABLE ADD table_constraint :
https://www.postgresql.org/docs/9.5/static/sql-altertable.html
<https://www.postgresql.org/docs/9.5/static/sql-altertable.html>
to add the FK references to word_games.
Hadn't considered "ALTER TABLE" but I'd be afraid of dump-restore
hazards here. Maybe pg_dump is smart enough to handle this correctly,
though - maybe by adding constraint definitions after all tables and
columns are present.
It does. Though the usual caveats about doing partial dumps apply, eg if
I had only specified -t fk_child below I would not get fk_parent
automatically:
postgres@test=# create table fk_child(id int, fk_id int);
CREATE TABLE
postgres@test=# create table fk_parent(id int, some_id int UNIQUE);
CREATE TABLE
postgres@test=# alter table fk_child ADD CONSTRAINT fk_constraint
FOREIGN KEY (fk_id) REFERENCES fk_parent(some_id);
ALTER TABLE
pg_dump -d test -U postgres -t fk_parent -t fk_child -f test.sql
--
-- Name: fk_child; Type: TABLE; Schema: public; Owner: postgres
--
CREATE TABLE fk_child (
id integer,
fk_id integer
);
ALTER TABLE fk_child OWNER TO postgres;
--
-- Name: fk_parent; Type: TABLE; Schema: public; Owner: postgres
--
CREATE TABLE fk_parent (
id integer,
some_id integer
);
ALTER TABLE fk_parent OWNER TO postgres;
--
-- Data for Name: fk_child; Type: TABLE DATA; Schema: public; Owner:
postgres
--
COPY fk_child (id, fk_id) FROM stdin;
\.
--
-- Data for Name: fk_parent; Type: TABLE DATA; Schema: public; Owner:
postgres
--
COPY fk_parent (id, some_id) FROM stdin;
\.
--
-- Name: fk_parent_some_id_key; Type: CONSTRAINT; Schema: public; Owner:
postgres
--
ALTER TABLE ONLY fk_parent
ADD CONSTRAINT fk_parent_some_id_key UNIQUE (some_id);
--
-- Name: fk_constraint; Type: FK CONSTRAINT; Schema: public; Owner: postgres
--
ALTER TABLE ONLY fk_child
ADD CONSTRAINT fk_constraint FOREIGN KEY (fk_id) REFERENCES
fk_parent(some_id);
David J.
--
Adrian Klaver
adrian.klaver@xxxxxxxxxxx
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