[英]PostgreSQL same trigger function to UPDATE on INSERT into different tables (using the same schema)
I have 100s of tables having the same schema and I have a trigger function to UPDATE some column whenever data is INSERTed into that table.我有 100 个具有相同架构的表,并且我有一个触发器函数可以在数据插入该表时更新某些列。
Table Schema:表架构:
CREATE TABLE symbol_daily_ohlc (
cdate date,
open numeric(8,2),
high numeric(8,2),
low numeric(8,2),
close numeric(8,2),
sma8 numeric(8,2)
);
Trigger function:触发功能:
create or replace function update_sma8() RETURNS TRIGGER AS
$$
BEGIN
UPDATE symbol_daily_ohlc d SET sma8 = s.simple_mov_avg
FROM
(
SELECT sec.cdate,AVG(sec.close)
OVER(ORDER BY sec.cdate ROWS BETWEEN 7 PRECEDING AND CURRENT ROW) AS
simple_mov_avg FROM symbol_daily_ohlc sec
)s where s.cdate = NEW.cdate --The newly inserted cdate
AND d.cdate = s.cdate;
RETURN NULL;
END $$ language plpgsql;
Trigger setup on table:表上的触发器设置:
CREATE TRIGGER trig_update_sma
AFTER INSERT ON symbol_daily_ohlc
FOR EACH ROW
EXECUTE PROCEDURE update_sma8();
This is working well for the given table ie symbol_daily_ohlc.这适用于给定的表,即 symbol_daily_ohlc。 I would like to use the same trigger function ie update_sma8() to be used with any table having the same schema (I don't want to rewrite the same function for different tables).我想使用相同的触发器函数,即 update_sma8() 与具有相同模式的任何表一起使用(我不想为不同的表重写相同的函数)。
I tried replacing the table name (ie symbol_daily_ohlc) with TG_TABLE_NAME, but that didn't work - thrown errors.我尝试用 TG_TABLE_NAME 替换表名(即 symbol_daily_ohlc),但这不起作用 - 抛出错误。 So how to do that?那么怎么做呢?
Reference: SQL trigger function to UPDATE daily moving average upon INSERT参考: 在插入时更新每日移动平均线的 SQL 触发器函数
You can have a same procedure that executes and returns a Trigger for all the tables, but you can't have a same Trigger for all your tables.您可以使用相同的过程为所有表执行并返回触发器,但不能为所有表使用相同的触发器。
Here's a block that dynamically creates a Trigger with table name suffix ( using EXECUTE format
)这是一个动态创建带有表名后缀的触发器的块(使用EXECUTE format
)
DO $$
declare
tabs RECORD;
BEGIN
for tabs IN
(select table_name,table_schema
from information_schema.tables where table_name
like 'symbol_daily_ohlc%'
-- and table_schema like '%'
) LOOP
EXECUTE format('CREATE TRIGGER check_update_%I
AFTER INSERT ON %I.%I
FOR EACH ROW
EXECUTE PROCEDURE update_sma8()',tabs.table_name,
tabs.table_schema
,tabs.table_name);
END LOOP;
END $$;
And here's your Trigger, which takes the table name dynamically from TG_TABLE_NAME
这是您的触发器,它从TG_TABLE_NAME
动态获取表名
create or replace function update_sma8() RETURNS TRIGGER AS
$$
BEGIN
EXECUTE format ('UPDATE %I d SET sma8 = s.simple_mov_avg
FROM
(
SELECT sec.cdate,AVG(sec.close)
OVER(ORDER BY sec.cdate ROWS BETWEEN 7 PRECEDING AND CURRENT ROW) AS
simple_mov_avg FROM %I sec
)s where s.cdate = %L --The newly inserted cdate
AND d.cdate = s.cdate',TG_TABLE_NAME,TG_TABLE_NAME,NEW.cdate);
RETURN NULL;
END $$ language plpgsql;
As others have suggested, it's not a good idea to have multiple tables with the same structure.正如其他人所建议的那样,拥有多个具有相同结构的表并不是一个好主意。 You should consider combining them into one table.您应该考虑将它们合并到一张表中。
I think you'll probably have to use SQL to generate SQL, then run the generated SQL.我认为您可能必须使用 SQL 来生成 SQL,然后运行生成的 SQL。 Something like:就像是:
select CONCAT('create or replace function update_sma8() RETURNS TRIGGER AS
$$
BEGIN
UPDATE ', table_name, ' d SET sma8 = s.simple_mov_avg
FROM
(
SELECT sec.cdate,AVG(sec.close)
OVER(ORDER BY sec.cdate ROWS BETWEEN 7 PRECEDING AND CURRENT ROW) AS
simple_mov_avg FROM ', table_name, '
)s where s.cdate = NEW.cdate --The newly inserted cdate
AND d.cdate = s.cdate;
RETURN NULL;
END $$ language plpgsql;
') from information_schema.tables
But really you should consider Gordon's advice (and my followup) and put all your data back in one table:但实际上,您应该考虑 Gordon 的建议(以及我的后续行动)并将所有数据放回一张表中:
SELECT CONCAT('INSERT INTO all_hist SELECT ''', table_name, ''', t.* FROM ', table_name) FROM information_schema.tables
This will generate a bunch of sqls that put all the table data into all_hist, a table that should have an identical schema to the other thousands, except for an additional column "symbol" or whatever..这将生成一堆将所有表数据放入 all_hist 的 sql,该表应该与其他数千个表具有相同的架构,除了附加列“符号”或其他任何内容。
You can use a similar trick to create yourself a bunch of views to recreate the thousands-table approach if you really want..如果你真的想要,你可以使用类似的技巧为自己创建一堆视图来重新创建千表方法。
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