问题描述
我正在尝试从游戏数据库中删除与用户ID相关的所有数据.
I'm trying to delete all data related to a user id from a game database.
有一张桌子可容纳所有比赛(每场比赛由3名球员参加):
There is a table holding all games (each played by 3 players):
# select * from pref_games where gid=321;
gid | rounds | finished
-----+--------+----------------------------
321 | 17 | 2011-10-26 17:16:04.074402
(1 row)
有一张桌子,上面列出了该游戏#321的玩家得分:
And there is a table holding players scores for that game #321:
# select * from pref_scores where gid=321;
id | gid | money | quit
----------------+-----+-------+------
OK531282114947 | 321 | 218 | f
OK501857527071 | 321 | -156 | f
OK429671947957 | 321 | -62 | f
当我在PostgreSQL的psql-prompt上尝试以下SELECT INTO语句时,它似乎按预期工作(并且关闭会话时,临时表消失了):
When I try the following SELECT INTO statement on the psql-prompt of PostgreSQL it seems to work as expected (and the temp table disappears when session is closed):
# select gid into temp temp_gids from pref_scores where id='OK446163742289';
SELECT
# select * from temp_gids ;
gid
------
1895
1946
1998
2094
2177
2215
(6 rows)
但是当我尝试创建我的PL/pgSQL过程时,出现错误:
But when I try to create my PL/pgSQL procedure I get error:
create or replace function pref_delete_user(_id varchar)
returns void as $BODY$
begin
select gid into temp temp_gids from pref_scores where id=_id;
delete from pref_scores where gid in
(select gid from temp_gids);
delete from pref_games where gid in
(select gid from temp_gids);
delete from pref_rep where author=_id;
delete from pref_rep where id=_id;
delete from pref_catch where id=_id;
delete from pref_game where id=_id;
delete from pref_hand where id=_id;
delete from pref_luck where id=_id;
delete from pref_match where id=_id;
delete from pref_misere where id=_id;
delete from pref_money where id=_id;
delete from pref_pass where id=_id;
delete from pref_status where id=_id;
delete from pref_users where id=_id;
end;
$BODY$ language plpgsql;
错误:
ERROR: syntax error at "temp"
DETAIL: Expected record variable, row variable, or list of scalar variables following INTO.
CONTEXT: compilation of PL/pgSQL function "pref_delete_user" near line 3
为什么会这样(这里不允许使用临时表?),以及将我要删除的女工的临时列表保存在哪里?
Why is that (temp tables not allowed here?) and where to save my temp list of the gid's to be deleted?
(而且我不希望使用在删除级联上",因为我还不习惯,而且我的脚本/数据库还没有为此准备).
(And I'd prefer not to use "on delete cascade" because I'm not used to it yet and my scripts/database isn't prepared for that yet).
推荐答案
您可以创建临时表,然后执行通常的INSERT ... SELECT
作为单独的操作:
You could create the temporary table and then do the usual INSERT ... SELECT
as separate operations:
create temporary table temp_gids (gid int not null) on commit drop;
insert into temp_gids (gid) select gid from pref_scores where id = _id;
如果您要创建表,还可以使用喜欢的选项要复制表的结构:
There's also a LIKE option to CREATE TABLE if you want to duplicate a table's structure:
但是我认为您只需要一个临时表来保存一些ID,这样可能就算过分了.
But I think you just need a temporary table to hold some IDs so that's probably overkill.
SELECT INTO
可以按您期望的方式运行 外部过程:
SELECT INTO
works as you expect outside a procedure:
SELECT INTO
用于将SELECT的结果存储在本地变量 :
SELECT INTO
is used to store the result of a SELECT in a local variable inside a PostgreSQL procedure:
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