On 08/23/2016 10:10 AM, Alexander Farber wrote:
Good evening,
with PostgreSQL 9.5.3 I am using the following table to store 2-player
games:
DROP TABLE IF EXISTS words_games;
CREATE TABLE words_games (
gid SERIAL PRIMARY KEY,
created timestamptz NOT NULL,
player1 integer REFERENCES words_users(uid) ON DELETE
CASCADE NOT NULL,
player2 integer REFERENCES words_users(uid) ON DELETE CASCADE,
played1 timestamptz,
played2 timestamptz,
-- mid1 integer REFERENCES words_moves(mid) ON DELETE CASCADE,
-- mid2 integer REFERENCES words_moves(mid) ON DELETE CASCADE,
score1 integer NOT NULL CHECK(score1 >= 0),
score2 integer NOT NULL CHECK(score2 >= 0),
hand1 varchar[7] NOT NULL,
hand2 varchar[7] NOT NULL,
pile varchar[116] NOT NULL,
letters varchar[15][15] NOT NULL,
values integer[15][15] NOT NULL,
bid integer NOT NULL REFERENCES words_boards ON DELETE CASCADE
);
This has worked well for me (when a user connects to the game server, I
send her all games she is taking part in), but then I have decided to
add another table to act as a "logging journal" for player moves:
DROP TABLE IF EXISTS words_moves;
DROP TYPE IF EXISTS words_action;
CREATE TABLE words_moves (
mid SERIAL PRIMARY KEY,
action words_action NOT NULL,
gid integer NOT NULL REFERENCES words_games ON DELETE CASCADE,
uid integer NOT NULL REFERENCES words_users ON DELETE CASCADE,
played timestamptz NOT NULL,
tiles jsonb,
score integer CHECK(score > 0)
);
Also, in the former table words_games I wanted to add references to the
latest moves performed by players:
-- mid1 integer REFERENCES words_moves(mid) ON DELETE CASCADE,
-- mid2 integer REFERENCES words_moves(mid) ON DELETE CASCADE,
The intention is: whenever a player connects to the server, sent her all
active games and status updates on the recent opponent moves.
However the 2 added columns do not work:
ERROR: relation "words_moves" does not exist
ERROR: relation "words_games" does not exist
ERROR: relation "words_moves" does not exist
So my question is if I can somehow "forward declare" the words_moves table?
Off the top of my head:
Change this:
--mid1 integer REFERENCES words_moves(mid) ON DELETE CASCADE,
--mid2 integer REFERENCES words_moves(mid) ON DELETE CASCADE,
to
mid1 integer
mid2 integer
and then after
CREATE TABLE words_moves ...
use ALTER TABLE ADD table_constraint :
https://www.postgresql.org/docs/9.5/static/sql-altertable.html
to add the FK references to word_games.
Here are all tables of my game for more context:
https://gist.github.com/afarber/c40b9fc5447335db7d24
Thank you
Alex
--
Adrian Klaver
adrian.klaver@xxxxxxxxxxx
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